var('a,b,t,x,y,x1,y1,z')
x=a*cos(t)
y=b*sin(t)
x1=diff(x,t)
y1=diff(y,t)
z=1/2*integrate((x*y1-y*x1),(t,0,2*pi))

Strang-9.4-2 (last edited 2010-12-17 05:35:12 by xxx)