Question

18 ) If sin θ = ⅘ then find cos θ. ​

Answer 1

Answer:

sin A=4/5

then cosA=3/5

Answer 2

Given

• Sin θ = ⅘

To find :

• Cos θ

Solution :

$\sf \: Sin θ = \frac{4}{5}$

Trigonometry identities

cos² θ = 1 - sin²θ .

Now ,

$\sf cos²θ = 1 -( \frac{4}{5} ) {}^{2}$

$\sf = 1 - \frac{13}{25}$

$\sf = \frac{25 - 16}{25}$

$\sf = \frac{9}{25}$

$\sf - - ) \cosθ = \sqrt \frac{9}{25}$

$\sf = \frac{3}{5}$

Therefore ,

$\sf cos θ = \frac{3}{5}$