Match each of the trigonometric expressions below with the equivalent non-trigonometric function from the following list. Enter the appropriate letter (A,B,C,D, or E) in each blank.

A. $\tan(\sin^{-1}(x/2))$
B. $\cos(\sin^{-1}(x/2))$
C. $(1/2)\sin(2\sin^{-1}(x/2))$
D. $\sin(\tan^{-1}(x/2))$
E. $\cos(\tan^{-1}(x/2))$



1. $\displaystyle \frac{x}{\sqrt{4 + x^2}}$
2. $\displaystyle \frac{x}{\sqrt{4 - x^2}}$
3. $\displaystyle \frac{2}{\sqrt{4 + x^2}}$
4. $\displaystyle \frac{x}{4}\sqrt{4 - x^2}$
5. $\displaystyle \frac{\sqrt{4 - x^2}}{2}$