Hey Everyone,

First time poster. I just have a couple questions that I was wondering if anyone could help me with (big test tomorrow). Thanks in advance.

1.

Given tan^-1 (x) = u :

a) State the domain of tan^-1 (x)

b) Find the exact value of sin (2tan^-1(5)).

c) Find an algebraic expression in x for f(x)=sin(2tan^-1(x))

2

Solve for x exactly:

a) 2cos^2(x) - sin(x) = 1

b) 2cos(x) + 1 < 0

3. A quadrilateral ABCD with AB=10, BC=10, CD=12 and DA=15, and angle A=50 degrees. Find the area of the quadrilateral.

Thanks again. I'll try to return the favor by answering some others questions at some point.