prove that: cos (sin^(-1) x) = (1-x^2)^(1/2)

please help. I don't even know where to start. (Worried)

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- September 30th 2008, 09:18 AMdee18identities (trig)
prove that: cos (sin^(-1) x) = (1-x^2)^(1/2)

please help. I don't even know where to start. (Worried)

- September 30th 2008, 09:54 AMChop Suey
is an angle. Therefore:

Recall that in right triangle trigonometry:

You can find the adj side using the Pythagorean theorem. Now we can find , which is:

- September 30th 2008, 09:58 AMChop Suey