#	differential equation solver;
#	solve differential equation and fractional differential equation for unknown y with independent variable x;
#	dsolve(eq,y)
#	there are 3 way to input derivative y: y', y(1,x), or ds(y,x,1)
#	there are 3 way to input second order derivative y: y'', y(2,x), or ds(y,x,2)
#	e.g. dsolve( y' = x*y, y)
#	dsolve( y(0.5,x)=y^2 )
#	dsolve(a_,y_,x_,q_) = If(isfree(a,y),d(a,x,-q), If(isfree(a/y,y),mittag(q,d(a/y,x,-q)), If(isfree(a,x), solve(d(1/a, y,-q)=x^q/q!,y) )));
#	dsolve(a_+b_, y_,x_,q_) := If(isfree(a,b,y), d(a+b,x,-q)+c_1+if(q>1, c_2*x,0), 
	If(isfree(a,b,x), solve(d(1/(a+b),y,-q)=x^q/q!,y)+if(q>1, c_2*x^2+c_1*x,c_1+x), 
	If(isfree(a,y) and isfree(d(b,y),y), 	block(dsolve:=d(d(b,y),x,-q),simplify(mittag(q,dsolve)*d(a*mittag(q,-dsolve),x,-q))+mittag(q,dsolve)), 
	If(isfree(b,y) and isfree(d(a,y),y), 	block(dsolve:=d(d(a,y),x,-q),simplify(mittag(q,dsolve)*d(b*mittag(q,-dsolve),x,-q))+mittag(q,dsolve)) ))));


dsolve(a_*y_,c_,x_,y_,1):=if(isconstant(a), block(xx:=dsolve(expand(a*replace(c,y,x(1,t)/a)),x,t,2), (x=xx, y=d(xx,t)/a)));
dsolve(a_,c_*x_,x_,y_,1):=if(isconstant(c), block(yy:=dsolve(expand(c*replace(a,x,y(1,t)/c)),y,t,2), (y=yy, x=d(yy,t)/c)));
 
dsolve(a_+y_, y_,x_,q_) := If(isfree(a,y), If(isfree(a,x), If(q>0, c_1*exp(x)-a, c_1*mittag(q,x^q) ), 
	c_1*exp(x)+psolution(1,a,y,x,q) ));
#dsolve(a_+b_*y, y_,x_,q_) := If(isfree(a,b,y), if(isfree(a,x), If(b>0, c_1*exp(b^(1/q)*x)-a/b,c_1*mittag(q,b^sgn(q)*x^abs(q)/(abs(q))!))-a/b, 
	If(b>0, c_1*exp(b^(1/q)*x)+psolution(b,a,y,x,q) ,c_1*mittag(abs(q),d(b,x,-q)) +psolution(b,a,y,x,q) )));
dsolve(z_+b_*y_, y_,x_,q_) := If(isfree(z,b,y), If(b>0, c_1*exp(b^(1/q)*x)+if(isfree(z,x),-a/b,psolution(b,z,y,x,q)), gsolution(b,y,x,q)+psolution(b,z,y,x,q) ));
dsolve(a_+b_*y_, y_,x_,q_) := If(isfree(a,b,y), If(b>0, c_1*exp(b^(1/q)*x)+if(isfree(a,x),-a/b,psolution(b,a,y,x,q)), gsolution(b,y,x,q)+psolution(b,a,y,x,q) ));

dsolve(a_*y_+b_*y_, y_,x_,q_) := If(isfree(a,b,y), c_1*mittag(q,d(a+b,x,-q)*q!) );
dsolve(a_*y_+y_, y_,x_,q_) := If(isfree(a,y), c_1*mittag(q,d(a+1,x,-q)*q!) );

#dsolve(a_+a_*y_, y_,x_,q_) := If(isfree(a,y), If(isfree(a,x), If(q>0, c_1*exp(a^(1/q)*x)-1, c_1*mittag(-q,1/a*x^(-q)/(-q)!)  ), 
	If(q>0,c_1*mittag(q,d(a,x,-q))-1, c_1*mittag(-q,d(a,x,-q))*d(a,x,-q) ) ));

#dsolve(x_^q_+y_, y_,x_,q_) := -x^q-q!;
#dsolve(x_^n_+b_*y_, y_,x_,q_) := If(isfree(b,x) and isfree(b,y), If(n==q, -x^q/b-q!/b^2, If(q>0, n!*x^(n+q)*mittag(q,1+n+q,b*x^q), gamma(n+1)*x^n*mittag(-q,n+1,1/b*x^(-q)) )));
#dsolve(x_^n_+b_*y_, y_,x_,q_) := If(isfree(b,x) and isfree(b,y), If(n==q, -x^n/b-q!/b^2, n!*x^(n+q)*mittag(q,1+n+q,b*x^q) ));
#dsolve(a_*x_^n_+b_*y_, y_,x_,q_) := If(isfree(a,b,x) and isfree(a,b,y), If(n==q, -a*x^n/b-a*q!/b^2, a*n!*x^(n+q)*mittag(q,1+n+q,b*x^q) ));

#dsolve(x_^n_+y, y_,x_,q_) := If(n==q, -x^n-n!, n!*x^(n+q)*mittag(q,1+n+q,x^q));
#dsolve(a_*x_^n_+y, y_,x_,q_) := If(isfree(a,x) and isfree(a,y), If(n==q, -a*x^n-a*n!, a*n!*x^(n+q)*mittag(q,1+n+q,x^q) ));
#dsolve(x_^n_+y+c_, y_,x_,q_) := If(isfree(c,x) and isfree(c,y), If(n==q, -x^n-n!-c, n!*x^(n+q)*mittag(q,1+n+q,x^q)-c));
#dsolve(a_*x_^n_+y+c_, y_,x_,q_) := If(isfree(a,c,x) and isfree(a,c,y), If(n==q, -a*x^n-a*n!-c, a*n!*x^(n+q)*mittag(q,1+n+q,x^q)-c ));
#dsolve(x_^n_+b_*y_+c_, y_,x_,q_) := If(isfree(b,c,x) and isfree(b,c,y), If(n==q, -x^n/b-q!/b^2-c/b, n!*x^(n+q)*mittag(q,1+n+q,b*x^q)-c/b ));
#dsolve(a_*x_^n_+b_*y_+c_, y_,x_,q_) := If(isfree(a,b,c,x) and isfree(a,b,c,y), If(n==q, -a*x^n/b-a*q!/b^2-c/b, a*n!*x^(n+q)*mittag(q,1+n+q,b*x^q)-c/b ));

#dsolve(a_*x_+b_*y_, y_,x_,q_) := If(isfree(a,b,x) and isfree(a,b,y), a*x^(1+q)*mittag(q,2+q,b*x^q));
#dsolve(a_*x_+y_, y_,x_,q_) := If(isfree(a,x) and isfree(a,y), a*x^(1+q)*mittag(q,2+q,x^q));
#dsolve(x_+b_*y_, y_,x_,q_) := If(isfree(b,x) and isfree(b,y), x^(1+q)*mittag(q,2+q,b*x^q) );
#dsolve(x_+y, y_,x_,q_) :=  x^(1+q)*mittag(q,2+q,x^q);
#dsolve(a_*x_+y_+c_, y_,x_,q_) := If(isfree(a,c,x) and isfree(a,c,y), If(q>0,a*x^(1+q)*mittag(q,2+q,x^q)-c,a*x^(1+q)*mittag(q,2+q,x^q) ));
#dsolve(x_+b_*y_+c_, y_,x_,q_) := If(isfree(b,c,x) and isfree(c,b,y), If(q>0,x^(1+q)*mittag(q,2+q,b*x^q)-c/b,x^(1+q)*mittag(q,2+q,b*x^q) ));
#dsolve(x_+y_+c_, y_,x_,q_) := If(isfree(c,x) and isfree(c,y), If(q>0,x^(1+q)*mittag(q,2+q,x^q)-c,x^(1+q)*mittag(q,2+q,x^q) ));
#dsolve(a_*x_+b_*y_+c_, y_,x_,q_) := If(isfree(a,b,c,x) and isfree(a,b,c,y), If(q>0, a*x^(1+q)*mittag(q,2+q,b*x^q)-c/b,a*x^(1+q)*mittag(q,2+q,b*x^q) ));
#dsolve(a_*x_+x_*y_, y_,x_,q_) := If(isfree(a,x) and isfree(a,y), c_1*mittag(q,x^(1+q)/(1+q)!)-a);
#dsolve(x_+b_*x_*y_, y_,x_,q_) := if(isfree(b,x) and isfree(a,y), c_1*mittag(abs(q),b*x^(1+abs(q))/(1+abs(q))!)-1/b);

dsolve(a_*x_+b_*x_*y(p_,x_), y_,x_,q_) := If(isfree(a,b,x) and isfree(a,b,y), c_1*d(mittag(q-p,b*x^(1+q-p)/(1+q-p)!)-a/b,x,-p));

#dsolve(b_*y^n_, y_,x_,q_) := If(isfree(b,y), If(isfree(b,x), b^(1-n)*fallingfactorial(q/(1-n),q)^(1/(n-1))*(x+c_1)^(q/(1-n)), (1/fallingfactorial(-n,q)*d(b,x,-q))^(1/(q-n)) ));
dsolve(y_^n_, y_,x_,q_) := fallingfactorial(-n,-q)^(1/(-q+n))*(x+c_1)^(1/(q-n)) ;

#dsolve(b_*y_, y_,x_,q_) := if(isfree(b,y), If(b>0, c_1*exp(b^(1/q)*x)+if(iseven(q), c_2*exp(-b^(1/q)*x),0), If(b<0, c_1*mittag(q,b*x^q),  c_1*mittag(q,d(b,x,-q)*q!) )));
dsolve(b_*y_, y_,x_,n_) := gsolution(b,y,x,n);
#dsolve(b_*x_*y_, y_,x_,q_) := If(isfree(b,y), c_1*mittag(q,b*x^(q+1)/(1+q)), c_1*mittag(q,d(b*x,x,-q)*q!) );
#dsolve(x_*y_, y_,x_,q_) :=  c_1*mittag(q,x^(1+q)/(1+q));
dsolve(y_, y_,x_,q_) := if(q==3, c_1*exp(x)+c_2*cos(x)+C_3*sin(x), if(iseven(q),c_1*exp(-x)+c_2*exp(x), c_1*exp(x) ));
dsolve(e^x_, y_,x_,q_) := exp(x)+if(q>0, sum(c(k+1)*x^k,k,0,ceil(q)-1,1),0 );
dsolve(0, y_,x_,q_) := if(q>0, sum(c(k+1)*x^k,k,0,ceil(q)-1,1) );

#dsolve(f_, y_,x_,1) :=dsolve(f, y,x);

dsolve(y(p_,x_),y_,x_,q_):= c_1*e^x+if(p>0,c_2,0);
dsolve(b_*y(p_,x_),y_,x_,q_):=if(isfree(b,y), if(b>0, c_1*exp(b^(1/(q-p))*x)+if(p>0,c_2,0), c_1*d(mittag(q-p,d(b,x,p-q)),x,-p)+if(p>0,c_2,0) ));
dsolve(y(p_,x_)+c_,y_,x_,q_):= d(dsolve(c+y,y,x,q-p),x,-p);
dsolve(b_*y(p_,x_)+c_,y_,x_,q_):=if(isfree(b,y), d(dsolve(c+b*y,y,x,q-p),x,-p));
dsolve(y(p_,x_)+c_*y, y_,x_,q_) := if(isfree(c,y) and isfree(c,x), if(q==2p, c_1*e^(((1-sqrt(1+4c))/2)^(1/p)*x)+c_2*e^(((1+sqrt(1+4c))/2)^(1/p)*x),c_1*exp(nsolve(y^q-y^p-c,y)*x) ));
dsolve(y(p_,x_)+y, y_,x_,q_) := if(q==2p, c_1*e^(((1-sqrt(5))/2)^(1/p)*x)+c_2*e^(((1+sqrt(5))/2)^(1/p)*x),c_1*exp(nsolve(y^q-y^p-1,y)*x) );
dsolve(b_*y(p_,x_)+c_*y, y_,x_,q_) := if(isfree(b,c,y) and isfree(b,c,x), if(q==2p, if(b*b+4c==0, c_1*exp((b/2)^(1/p)*x)+c_2*exp((b/2)^(1/p)*x)*x, 
	c_1*e^(((b-sqrt(b^2+4c))/2)^(1/p)*x)+c_2*e^(((b+sqrt(b^2+4c))/2)^(1/p)*x)), 
	if(b+c==1, c_1*e^(x),c_1*exp(nsolve(y^q-b*y^p-c,y)*x) )));
dsolve(b_*y(p_,x_)+y, y_,x_,q_) := if(isfree(b,y) and isfree(b,x), if(q==2p, c_1*e^(((b-sqrt(b^2+4))/2)^(1/p)*x)+c_2*e^(((b+sqrt(b^2+4))/2)^(1/p)*x),c_1*exp(nsolve(y^q-b*y^p-1,y)*x) ));

dsolve(b_*y(p_,x_)+c_*y+d_, y_,x_,q_) := if(isfree(b,c,d,y) and isfree(b,c,d,x), dsolve(b*y(p,x)+c*y, y,x,q)-d/c, dsolve(b*y(p,x)+c*y, y,x,q)+psolution(b,p,c,d,y,x,q) );
dsolve(b_*y(p_,x_)+y+d_, y_,x_,q_) := if(isfree(b,d,y) and isfree(b,d,x), dsolve(b*y(p,x)+y, y,x,q)-d, dsolve(b*y(p,x)+y, y,x,q)+psolution(b,p,1,d,y,x,q) );
dsolve(y(p_,x_)+c_*y+d_, y_,x_,q_) := if(isfree(c,d,y) and isfree(c,d,x), dsolve(y(p,x)+c*y, y,x,q)-d/c, dsolve(y(p,x)+c*y, y,x,q)+psolution(1,p,c,d,y,x,q) );
dsolve(y(p_,x_)+y+d_, y_,x_,q_) := if(isfree(d,y) and isfree(d,x), dsolve(y(p,x)+y, y,x,q)-d, dsolve(y(p,x)+y, y,x,q)+psolution(1,p,1,d,y,x,q) );

dsolve(a_ and b_, y_,x_,p_) :=	dsolve(a, y,x,p) and dsolve(b, y,x,p);

dsolve(a_+b_*y_, y_,x_,-1) := if(isfree(a,b,y), if(isfree(b,x), c_1*exp(integrate((1-d(b,x))/b,x)), c_1*exp(integrate((1-d(b,x))/b,x))+psolution((1-d(b,x))/b,-d(a,x)/b,y,x,1) ));

dsolve(y(1,x_),y_,x_,3):=c_1+c_2*e^(x)+C_3*e^(-x);
dsolve(y(2,x_),y_,x_,3):=c_1+c_2*e^(x)+C_3*x;
dsolve(b_*y(1,x_),y_,x_,3):=gsolution(0,b,y,x,2)+C_3;
dsolve(b_*y(2,x_),y_,x_,3):=c_1+c_2*e^(int(b,x))+C_3*x;

dsolve(a_+b_*y_, y_,x_,2) := if(isfree(a,b,y), if(isfree(a,b,x), gsolution(0,b,y,x,2)-a/b, if(a==b, gsolution(0,b,y,x,2), gsolution(0,b,y,x,2)+psolution(b,a,y,x,2) )));
#dsolve(a_+y_, y_,x_,2) := if(isfree(a,y),if(isfree(a,x), c_1*exp(x)+c_2*exp(-x)-a, c_1*exp(x)+c_2*exp(-x)-1/2*exp(-x)*int(exp(x)*a,x)+1/2*exp(x)*int(exp(-x)*a,x) ));
dsolve(a_+y_, y_,x_,2) := if(isfree(a,y),if(isfree(a,x), c_1*exp(x)+c_2*exp(-x)-a, c_1*exp(x)+c_2*exp(-x)+psolution(1,a,y,x,2) ));
dsolve(x_+y_, y_,x_,2) := c_1*exp(x)+c_2*exp(-x)-x;
dsolve(x_+b_*y_, y_,x_,2) := if(isfree(b,x), gsolution(0,b,y,x,2)-x/b, gsolution(0,b,y,x,2)+psolution(b,x,y,x,2) );
dsolve(a_*x_+b_*y_, y_,x_,2) := if(isfree(a,b,x), gsolution(0,b,y,x,2)-a*x/b, gsolution(0,b,y,x,2)+psolution(b,a*x,y,x,2) );
dsolve(a_*x_+b_*y_+c_, y_,x_,2) := if(isfree(a,b,c,x), gsolution(0,b,y,x,2)-a*x/b-c/b, gsolution(0,b,y,x,2)-a*x/b+psolution(b,c,y,x,2) );

dsolve(y(1,x_)^n_,y_,x_,2):= if(n==2, c_2 - log(c_1 + x), c_2 - (-(n - 1)* (c_1 + x))^(1/(1 - n) + 1)/(n - 2));
dsolve(b_*y(1,x_)^n_,y_,x_,2):= if(isfree(b,y) and isfree(b,x), if(n==2, c_2 - log(c_1 + b*x)/b,c_2 - (-(n - 1)* (c_1 + b*x))^(1/(1 - n) + 1)/(n - 2)/b ));
dsolve(b_*y_, y_,x_,2) := if(isfree(b,y), gsolution(0,b,y,x,2) );
dsolve(x_*y_, y_,x_,2) := c_1*AiryAi(x)+c_2*AiryBi(x);
#dsolve(a_*x_*y_, y_,x_,2) := if(isfree(a,x) and isfree(a,y), c_1*AiryAi(cbrt(a)*x)+c_2*AiryBi(cbrt(a)*x));
dsolve(a_*x_*y_, y_,x_,2) := if(isfree(a,x) and isfree(a,y), gsolution(a*x,y,x,2) );
dsolve(c_/x_^2*y_, y_,x_,2) := if(isfree(c,x), gsolution(0,c/x^2,y,x,2) );
dsolve(b_*y(1,x_),y_,x_,2):=if(isfree(b,y),if(isfree(b,x), c_1+c_2*e^(b*x), c_2*integrate(exp(int(b,x)),x)+c_1 ));
dsolve(xy_*y(1,x_),xy_,x_,2):= sqrt(2)*tan(sqrt(2)/2*x+c_1);
dsolve(xy_*y(1,x_)^2,xy_,x_,2):=sqrt(2)* inverseerf((sqrt(2 pi) *c_1* x + sqrt(2 pi)* c_2 )/pi);
dsolve(b_*xy_*y(1,x_),xy_,x_,2):=if(isfree(b,xy) and isfree(b,x), sqrt(2)* sqrt(c_1)* tan(1/2 *(sqrt(2)* sqrt(b)* sqrt(c_1)* x + sqrt(2)* sqrt(b)* sqrt(c_1))) );
dsolve(-xy*y(1,x_),xy_,x_,2):= sqrt(2)*tanh(sqrt(2)/2*x+c_1);

dsolve(c_+y(1,x_),y_,x_,2):=if(isfree(c,y),if(isfree(c,x), c_1+c_2*e^x-c*x, c_1+c_2*e^(x)+integrate(exp(x)*int(exp(-x)*c,x),x) ));
#dsolve(c_+b_*y(1,x_),y_,x_,2):=if(isfree(b,c,y),if(isfree(b,c,x), c_1+c_2*e^(b*x)-c*x/b, integrate(dsolve(c+b*y,y,x),x)+c_2 ));
#dsolve(c_+b_*y(1,x_),y_,x_,2):=if(isfree(b,c,y),if(isfree(b,c,x), c_1+c_2*e^(b*x)-c*x/b, c_1+c_2*e^(b*x)+integrate(exp(b*x)*int(exp(-b*x)*c,x),x) ));
dsolve(c_+b_*y(1,x_),y_,x_,2):=if(isfree(b,c,y),if(isfree(b,c,x), c_1+c_2*e^(b*x)-c*x/b, c_2+int(c_1*e^(int(b,x))+psolution(b,c,y,x,1),x) ));
dsolve(xy+y(1,x_),xy_,x_,2):= c_1*e^((1-sqrt(5))/2*x)+c_2*e^((1+sqrt(5))/2*x);
dsolve(b_*y(1,x_)+xy_,xy_,x_,2):=if(isfree(b,xy), gsolution(b,1,xy,x,2) );
dsolve(y(1,x_)+c_*xy_,xy_,x_,2):=if(isfree(c,xy), gsolution(1,c,xy,x,2) );
dsolve(b_*y(1,x_)+c_*xy_,xy_,x_,2):=if(isfree(b,c,xy), gsolution(b,c,xy,x,2) );

dsolve(y(1,x_)+xy_+d_,xy_,x_,2):=if(isfree(d,xy) and isfree(d,x), gsolution(1,1,xy,x,2)-d*x-d, gsolution(1,1,xy,x,2)+psolution(1,1,1,d,xy,x,2));
dsolve(b_*y(1,x_)+xy_+d_,xy_,x_,2):=if(isfree(b,d,xy) and isfree(b,d,x), gsolution(b,1,xy,x,2)-d*x-d*b, gsolution(b,1,xy,x,2) +psolution(b,1,1,d,xy,x,2));
dsolve(y(1,x_)+c_*xy_+d_,xy_,x_,2):=if(isfree(c,d,xy) and isfree(c,d,x), gsolution(1,c,xy,x,2)-d*x/c-d/c^2, gsolution(1,c,xy,x,2)+psolution(1,1,c,d,xy,x,2));
dsolve(b_*y(1,x_)+c_*xy_+d_,xy_,x_,2):=if(isfree(b,c,d,xy),if(isfree(b,c,d,x), gsolution(b,c,xy,x,2)-d*x/b-d/c*b, gsolution(b,c,xy,x,2)+psolution(b,1,c,d,xy,x,2) ));

#dsolve(b_*y(1,x_)+c_*xy_+d_,xy_,x_,2):=if(isfree(b,c,d,xy) and isfree(b,c,d,x), gsolution(b,c,xy,x,2)-d*x/b-d/c/b, 
	if(b*b+4c==0, c_1*exp(b/2*x)+c_2*exp(b/2*x)*x+expand(exp(b/2*x)*x*int(exp(-b/2*x)*d,x)-exp(b/2*x)*int(d*exp(-b/2*x)*x,x)),
	gsolution(b,c,xy,x,2)+ expand(-e^((b-sqrt(b^2+4c))/2*x)*int(d*e^((-b+sqrt(b^2+4c))/2*x),x)+e^((b+sqrt(b^2+4c))/2*x)*int(d*e^((-b-sqrt(b^2+4c))/2*x),x)/sqrt(b*b+4c)) 
 ));

dsolve(y_, y_,x_,2) := c_1*exp(-x)+c_2*exp(x);
dsolve(y_, y_,x_,4) := c_1*exp(-x)+c_2*exp(x)+c(3)*cos(x)+c(4)*sin(x);


#dsolve(a_+b_, y_,x_) := If(isfree(a,b,y), integrate(a+b,x)+c_1, 
	If(has(a,y) and has(b,y) and isfree(d(a+b,y),y), exp(integrate(d(a+b,y),x))*c_1, 
	If(isfree(b,y) and isfree(d(a,y),y),  	block(dsolve:=int(d(a,y),x),exp(dsolve)*int(b*exp(-dsolve),x)+exp(dsolve)*c_1), 
	If(isfree(a,y) and isfree(d(b,y),y), 	block(dsolve:=int(d(b,y),x),exp(dsolve)*int(a*exp(-dsolve),x)+exp(dsolve)*c_1) ))));
#dsolve(a_+b_*y_,y_,x_):=If(isfree(a,b,y), If(isfree(a,b,x), c_1*exp(b*x)-a/b,
	block(dsolve:=integrate(b,x), expand(exp(dsolve)*integrate(a*exp(-dsolve),x))+exp(dsolve)*c_1 ) ));

dsolve(a_+y_*z_,y_,x_,1):=If(isfree(a,z,y), If(isfree(a,z,x), c_1*exp(z*x)-a/z,	c_1*exp(integrate(z,x))+psolution(z,a,y,x,1) ));
dsolve(b_*y_+z_,b_,x_,1):=If(isfree(z,y,b), If(isfree(z,y,x), c_1*exp(y*x)-z/y,	c_1*exp(integrate(y,x))+psolution(y,z,b,x,1) ));
dsolve(b_*y_+z_,y_,x_,1):=If(isfree(z,b,y), If(isfree(z,b,x), c_1*exp(b*x)-z/b,	c_1*exp(integrate(b,x))+psolution(b,z,y,x,1) ));
dsolve(a_+b_*y_,y_,x_,1):=If(isfree(a,b,y), If(isfree(a,b,x), c_1*exp(b*x)-a/b,	c_1*exp(integrate(b,x))+psolution(b,a,y,x,1) ));
dsolve(a_+a_*y_,y_,x_,1):=If(isfree(a,y), c_1*exp(integrate(a,x))-1);

dsolve(a_+y_,y_,x_,1):=If(isfree(a,y), If(isfree(a,x), c_1*exp(x)-a, expand(exp(x)*integrate(a*exp(-x),x))+exp(x)*c_1 ));
dsolve(y_+z_,y_,x_,1):=If(isfree(z,y), If(isfree(z,x), c_1*exp(x)-z, expand(exp(x)*integrate(z*exp(-x),x))+exp(x)*c_1 ));

dsolve(a_*y_+y_,y_,x_,q):=If(isfree(a,y), c_1*mittag(q,d(a+1,y,-q)*q!) );
dsolve(a_*y_+b_*y_,y_,x_,q_):=If(isfree(a,b,y), c_1*mittag(q,d(a+b,x,-q)*q!) );
dsolve(x_+x_*y_, x_,y_,q_) := c_1*mittag(q,d(1+y,y,-q)*q!);
dsolve(x_+b_*x_*y_, x_,y_,q_) := If(isfree(b,x), c_1*mittag(q,d(1+b*y,y,-q)*q!) );
dsolve(a_*x_+b_*x_*y_, x_,y_,q_) := If(isfree(a,b,x), c_1*mittag(q,d(a+b*y,y,-q)*q!) );

dsolve(a_*y_+b_*y_^n_,y_,x_,1):=If(isfree(a,b,y) , block(dsolve:=integrate(a,x), exp(dsolve)*(c_1+(1-n)*integrate(b*exp((n-1)*dsolve),x))^(1/(1-n)) ) );
dsolve(a_*y_+y_^n_,y_,x_,1):=If(isfree(a,n,y) , block(dsolve:=integrate(a,x), exp(dsolve)*(c_1+(1-n)*integrate(exp((n-1)*dsolve),x))^(1/(1-n)) ) );
dsolve(y_+y_^n_,y_,x_,1):= exp(x)*(c_1-exp((n-1)*x))^(1/(1-n));
dsolve(x_+y_, y_,x_,1) := c_1*exp(x)-x-1;
dsolve(x_+y_, x_,y_,1) := c_1*exp(y)-y-1;

#dsolve(a_*x_+y_, y_,x_) := If(isfree(a, x) and isfree(a, y), -a*x-a);
#dsolve(x_+b_*y_,y_,x_)  := If(isfree(b, x) and isfree(b, y), -1/b*x-1/b^2);
#dsolve(a_*x_+b_*y_,y_,x_):=If(isfree(a,b, x) and isfree(a,b, y), -a/b*x-a/b^2);
#dsolve(x_+y_+c_, y_,x_) := If(isfree(c,x) and isfree(c,y), -x-1-c);
#dsolve(x_+b_*y_+c_, y_,x_) := If(isfree(b,c,x) and isfree(b,c,y), -1/b*x-1/b^2-c/b);
#dsolve(a_*x_+y_+c_, y_,x_) := If(isfree(a,c,x) and isfree(a,c,y), -a*x-a-c);
#dsolve(a_*x_+b_*y_+c_, y_,x_) := If(isfree(a,b,c,x) and isfree(a,b,c,y), -a/b*x-a/b^2-c/b);

dsolve(f_^n_,y_,x_,1) := if(has(f,x) and has(f,y) and isfree(n,x) and isfree(n,y),dsolve(pow(f_,n_),y_,x_,1));
dsolve(b_*y_, y_,x_,1) := If(isfree(b,y), c_1*exp(integrate(b,x)));
dsolve(b_*y_^n_, y_,x_,1) := If(isfree(b,y), ((1-n)*integrate(b,x)+c_1)^(1/(1-n)) );

dsolve(z_/(b_+c_), y_,x_,n_) := x=dsolve(b/z+c/z,x,y,n);
dsolve(a_/(b_+c_), y_,x_,n_) := x=dsolve(b/a+c/a,x,y,n);
dsolve(1/(b_+c_), y_,x_,n_) := x=dsolve(b+c,x,y,n);

dsolve(y_,y_,x_,1) := c_1*exp(x);
#dsolve(y(n_,x_),y_,x_) := c_1*exp(x);


#dsolve(f_,y(x_)) := dsolve(replace(d(y(x),x)-f,y(x),y),y);
#dsolve(a_=b_,y_):= if(has(a,ds(y,x,2)),dsolve(ds(y,x,2)-a+b,y,x,2), if(has(a,ds(y)),dsolve(ds(y)-a+b,y,x), if(has(a,dy),dsolve(dy/dx-a+b,y,x), dsolve(a-b,y)  )));
#dsolve(y'=f_,y) := dsolve(f,y,x);
#dsolve(y''=f_,y) := dsolve(f,y,x,2);
#dsolve(dy/dx=f_,y) := dsolve(f,y,x);
#dsolve(d(y(x_),x_)=f_,y(x_)) := dsolve(replace(f,y(x),y),y,x);
#dsolve(ds(y_)=a_,y_) := dsolve(a,y,x);
#dsolve(ds(y_,x_)=a_,y_) := dsolve(a,y,x);
#dsolve(ds(y_,x_,q_)=a_,y_):= dsolve(a,y,x,q);
#dsolve(a_+ds(y_,x_,q_),y_):= dsolve(-a,y,x,q);
#dsolve(ds(y_,x_,q_)+z_,y_):= dsolve(-z,y,x,q);
#dsolve(ds(y_,x_,q_)+f_+z_,y_):= dsolve(-f-z,y,x,q);
#dsolve(a_+ds(y_,x_,q_)+z_,y_):= dsolve(-a-z,y,x,q);

dsolve(a_+y(q_,x_),y_):= dsolve(-a,y,x,q);
dsolve(a_+b_*y(q_,x_),y_):= dsolve(-expand(a/b),y,x,q);
dsolve(a_+y(q_,x_),y(x_)):= dsolve(-replace(a,y(x),y),y,x,q);
dsolve(y(p_,x_)^n_+b_,y_):= dsolve(solve(replace(b,y(p,x),yy)+yy^n,yy),y,x,p);
dsolve(a_*y(p_,x_)^n_+b_,y_):= dsolve(solve(expand(replace(b,y(p,x),yy)/a)+yy^n,yy),y,x,p);

#dsolve(x_^2*y(2,x_)+b_*x_*y(1,x_)+c_*xy_+d_,xy_):= if(isfree(b,c,d,xy), gsolution(b-1,c,xy,x,2)+int(replace(d,x,e^x),x) );

dsolve(a_=b_,y_):=dsolve(toy(a-b),y);

dsolve(integrates(f_,t_,a_,b_)=c_,y_) := dsolve(toy(d(integrates(f,t,a,b)-c,x)),y);
dsolve(y(n_,t_)=a_,y_) := dsolve(toy(a),y,t,n);
dsolve(x(n_,t_)=a_,y_) := dsolve(tox(a),y,t,n);

#dsolve(b_+x(n_,t_),d_+y(n_,t_)):= (x=dsolve(-b,x,t,n) and y=dsolve(-d,y,t,n));
#dsolve(b_+x(n_,t_),d_+x_+y(n_,t_)):= block(xx:=dsolve(-b,x,t,n), x=xx and y=dsolve(-d-xx,y,t,n));
dsolve(b_+x(n_,t_),d_+y(m_,t_)):= if(hasnot(b,y(t)) and hasnot(d,x(t)), (x=dsolve(-b,x(t),t,n), y=dsolve(-d,y(t),t,m)), 
	if(hasnot(b,y(t)),block(xx:=dsolve(-b,x(t),t,n), (x=xx, y=dsolve(-replace(d,x(t),xx),y(t),t,m))),
	if(hasnot(d,x(t)),block(xx:=dsolve(-d,y(t),t,m), (y=xx, x=dsolve(-replace(b,y(t),xx),x(t),t,n))) )));

dsolve(a_=b_,c_=d_):= dsolve(tox(a=b),toyt(c-d));
dsolve(x(n_,t_)=b_,d_+y(m_,t_)):= block(bb:=replace(replace(b,x(t),x),y(t),y),dd:= replace(replace(-d,x(t),x),y(t),y),
	if(hasnot(bb,y),block(xx:=dsolve(bb,x,t,n), (x=xx, y=dsolve(replace(dd,x,xx),y,t,m))),
	if(hasnot(dd,x),block(xx:=dsolve(dd,y,t,m), (y=xx, x=dsolve(replace(bb,y,xx),x,t,n))),
	if(n==m, dsolve(bb,dd,x,y,n) ))));

dsolve(x(n_,t_)=a_,y(n_,t_)=c_):= if(hasnot(a,y), block(xx:=dsolve(a,x,t,n), (x=xx, y=dsolve(replace(c,x,xx),y,t,n))), 
	if(hasnot(c,x), block(yy:=dsolve(c,y,t,n), (y=yy, x=dsolve(replace(c,y,yy),x,t,n))), 
	dsolve(a,c,x,y,n) ));
dsolve(x'=f_,y'=g_):= dsolve(x(1,t)=f,y(1,t)=g);


dsolve(a_):=dsolve(replace(toy(a),y(x),y),y);