SOLUTION: please help me varify tan(sin<sup>-1</sup>(x)) = {{{x/sqrt(1-x^2)}}}

Algebra ->  Geometry-proofs -> SOLUTION: please help me varify tan(sin<sup>-1</sup>(x)) = {{{x/sqrt(1-x^2)}}}       Log On


   



Question 689775: please help me varify tan(sin-1(x)) = x%2Fsqrt%281-x%5E2%29
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!
tan(sin-1(x))

First let's find sin-1(x).

sin-1(x) means "The ANGLE whose SINE is x".

So let's draw a right triangle with an ANGLE whose SINE is x.

First we observe that SINE%22%22=%22%22OPPOSITE%2FHYPOTENUSE

Second, we observe that x = x%2F1.  Se we draw a right triangle
with x for the OPPOSITE side and 1 for the HYPOTENUSE, the Pythagorean
theorem tells us that the ADJACENT side in √1-x²

Here's a right triangle which contains an angle whose sine is x%2F1 or x.



Let's go back to the original problem:

tan(sin-1(x))

We have sin-1x as an angle in the right triangle above,
so all we need is the TANGENT of the angle marked sin-1x.
Since TANGENT%22%22=%22%22OPPOSITE%2FADJACENT, 

tan(sin-1(x)) = x%2Fsqrt%281-x%5E2%29

We have now verified that.

Edwin