Question

if sin theta =2/5 find the value of cos theta and tan theta​

Answer 1

$sin \theta = \frac{2}{5} \\ cos \theta = \sqrt{1 - {sin}^{2} \theta} \\ = \sqrt{1 - \frac{4}{25} } \\ = \sqrt{ \frac{21}{25} } \\ = \frac{ \sqrt{21} }{5} \\ tan \theta = \frac{sin \theta}{cos \theta} \\ = \frac{ \frac{2}{5} }{ \frac{ \sqrt{21} }{5} } \\ = \frac{2}{ \sqrt{21} }$