Question

If sin theta = 1/2 , find the value of cos20

it's a optional mathematics Questions please solve him​

Answer 1

cos2θ =
`(1)/(2)`

Explanation:

Using the identity

cos2θ = 1 - 2sin²θ

= 1 - 2(
`(1)/(2)` )²

= 1 - 2(
`(1)/(4)` )

= 1 -
`(1)/(2)`

=
`(1)/(2)`

Answer 2

√3/2

Explanation:

p/h=1/2

Using Pythagoras Theorem

b=√3

cos=√3/2

cos20= √3/2*20

= 10√3