Hello everyone,
I"m having troubles finding what expression I should u-sub. here's the problem.
Code:
definate integral, from 0 to pi/2   [cos(x)/(1+sin^2(x))]dx
I tried
u = 1+sinx;
du = cosx dx;

but that won't due because the sin^2(x),
like i can't do this:
integral symbol du/u^2
because (1+sin^2 x ) != (1+sinx)^2 or is it?

also is this true or false? 2
definate integral from -1 to 2 1/x dx = [ln|x|] = ln2 - ln1 = ln2
-1

Thanks!