sin-1-2-5-find-cos-and-tan-

Question Number 126700 by Eric002 last updated on 23/Dec/20

θ = {s i n}^{- 1} (\frac{2}{5}) f i n d c o s (θ) a n d t a n (θ)

Answered by akornes last updated on 23/Dec/20

c o s θ = \pm \frac{\sqrt{21}}{5} a n d t a n θ = \pm \frac{2 \sqrt{21}}{21}

Commented by MJS_new last updated on 23/Dec/20

how can the \cos and \tan of an angle in the

first quadrant be < 0 ? ? ?

Answered by MJS_new last updated on 23/Dec/20

θ = \sin^{- 1} \frac{2}{5} \Rightarrow θ \approx 23.58 °

\Rightarrow \cos θ = \sqrt{1 - {(\frac{2}{5})}^{2}} = \frac{\sqrt{21}}{5}; \tan θ = \frac{\frac{2}{5}}{\sqrt{1 - {(\frac{2}{5})}^{2}}} = \frac{2 \sqrt{21}}{21}

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