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**RD33** (1 pt) Find the exact value (NO DECIMALS) of each expression by sketching a triangle:

A) sin(cos^-1(3/5))

b) cos(sin^-1(4/5))

I have no idea where to start

**A)**

Use the fact thatcos^2(x)+sin^2(x) = 1

We have cos^-1(3/5) <=> cos(x) = 3/5 => cos^2(x) = 9/25

Using the trigonometric one we get9/25+sin^2(x) = 25/25 <=> sin^2(x) = 16/25 <=> sin(x) = +/- 4/5

But since cos^-1 is defined for 0 to pi, the only solution is sin(x) = 4/5

By this we now have the expressionsin(cos^-1(3/5)) = sin(sin^-1(4/5)) = 4/5

I leave the second one as exercise for you!