y1=cos(x);y2=sin(x)
y1=var('y1');y2=var('y2')
w =var('w')
expand(w==(cos(x)^2+sin(x)^2)==1)#this is divided into W(y1),W(y2)
W(y1)=cos(x)*cos(x)
w(y2)=sin(x)*sin(x)
integral(w(y1),x)
integral(w(y2),x)
def f(X):
    return[-cos(x)*integral(sin(x)*sec(x))+sin(x)*integral(cos(x)*sec(x))]#made into a function
f(x)
c1,c2=var('c1,c2')
yh=add(c1*y1,c2*y2)
y=add(yh,f(x))
y==(c1+log(cos(x))]*cos(x)+(c2+x)*sin(x))

Kreyszig-sec 2.10-1 (last edited 2010-12-17 12:32:04 by prasad)