How in the world do you solve the math question like this....?(trig inverse function)

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1

<p>arccos(x)=root2/2 (root 2 over 2)</p>

<p>how do you find x without calulator?
Thanks in advance.</p>

2

<p>nvm i did this wrong</p>

3

<p>The only way is to know the unit circle, otherwise, you're sunk</p>

4

<p>I don't think you can solve this one without a calculator. Are you sure you got your equation right?</p>

5

<p>sqrt(2)/2 should be a familiar number in the unit circle (cos 45 degrees, sin 45 degrees), which is the only way to get the answer (45 degrees)</p>

6

<p>Oh wait, now that i read it, arccos(x), huh? Well maybe there's a mistake in the problem, but sqrt(2)/2 is one of those familiar unit circle numbers, that's why I jumped to that conclusion. My bad.</p>

7

<p>Yeah, it doesn't seem like you could do this without a calculator. Those other trig identities won't be of much use because there doesn't seem to be a way to split sqrt(2)/2 up into the sum of things you could easily find the cosine or sine of. Maybe you misread the question?</p>