Suppose we let
, so that
.
Also, recall the double angle identity for cosine:

So, we can rewrite and compute the integral using the substitution, as





72 I think it is I believe
2x - 3(x-1) = -1
2x -3x + 3 = -1
-1x + 3 = -1
-1x = -4
x = 4
y = 4 - 1
y = 3
The second shape is double the first so you would do AB = 2 and then times by 2 as its double and you will get 4
answer = 4