#2 page 751

> y1:=x->sin(2*x);

> diff(y1(x),x,x)+4*y1(x)=0;

> y2:=x->sin(2*x)*v(x);

> diff(y2(x),x,x)+4*y2(x)=0;

> 4*cos(2*x)*z(x)+sin(2*x)*diff(z(x),x) = 0;

> solve(%,diff(z(x),x));

> "[Maple Math]">

> int(1/z,z)=int(-4*cos(2*x)/sin(2*x),x);

> solve(%,z);

> int(%,x);

> *sin(2*x);

> y2:=unapply(%,x);

> diff(y2(x),x,x)+4*y2(x)=0;