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I need to solve for x, where x is between -pi/2 and pi/2.

sin(x)=-1/sqrt(2) Anyone know how ?

 Jun 23, 2016
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\(sin(x)=-\frac{1}{\sqrt{2}}\)

 

\({sin}^{-1}(sin(x))={sin}^{-1}(-\frac{1}{\sqrt{2}})\)

 

\(x=-\frac{\pi}{4}\)

 

That is how you do it with a calculator.  To get to the answer without using a calculator, looking at the unit circle, what point on the unit circle between \(-\frac{\pi}{2}\) and \(\frac{\pi}{2}\) is the y value equal to \(-\frac{1}{\sqrt{2}}?\)  The point on the unit circle is actually a point that is easily memorized.

 Jun 24, 2016

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