Question

if sin 3a=1 then find value of cos2a​

Answer 1

Answer:

0.5

Step-by-step explanation:

sin(3a)  = 1

 sin(90)  = 1

Therefore,

3a = 90

a =  $\frac{90}{3}$  = 30

$\cos(2a) = \cos(2 \times 30) = \cos(60) = \frac{1}{2}$

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