If $sin x = \frac{4}{5}$ $sin x= 4/5$ , how do you find cos x?

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Answer 1 · 2015-04-16T18:20:57

cosx= $\frac{3}{5}$ $3/5$

Use Trignometrical identity cosx = $\sqrt{1 - {sin}^{2} x}$ $sqrt(1-sin^2 x)$

cos x = $\sqrt{1 - \frac{16}{25}}$ $sqrt(1 -16/25)$ = $\sqrt{\frac{9}{25}}$ $sqrt(9/25)$ = $\frac{3}{5}$ $3/5$ to be the value in the first quadranr.

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