Question

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If sinA    is   ¾   then cosA  is ​

Answer 1

Given :

$\rm{\sin\:A=\dfrac{3}{4}}$

To Find :

The value of cosA

Answer :

We have, $\rm{\sin\:A=\dfrac{3}{4}}$

We know that

$\rm{\sin^2x+\cos^2x=1}$

$\implies\rm{\cos\:A=\sqrt{1-\sin^2A}}$

$\implies\rm{\cos\:A=\sqrt{1-(\dfrac{3}{4})^2}}$

$\implies\rm{\cos\:A=\sqrt{1-\dfrac{9}{16}}}$

$\implies\rm{\cos\:A=\sqrt{\dfrac{16-9}{16}}}$

$\implies\rm{\cos\:A=\dfrac{\sqrt{7}}{4}}$

Therefore ,The value of cosA =√7/4.