I think i know this, but im not exactly sure....

1. simplify:

(x^(-2)-y^(-2))(y+x)^(-1)

2. If f(x) = (4/x), find and simplify (f(x+h)-f(x))/(h)

3. express the area A of an equilateral triangle as a function of the length S of a side of the triangle.

4. solve for the real number x: ln x - ln(x-1) = 1

5. solve for x in the interval [0, 2(pi)]: sin2x-sinx = 0

thanks!!