352,911 views
24 votes
24 votes
If sin theta = 1/2 , find the value of cos20

it's a optional mathematics Questions please solve him​

User TrazeK
by
2.7k points

2 Answers

19 votes
19 votes

Answer:

cos2θ =
(1)/(2)

Explanation:

Using the identity

cos2θ = 1 - 2sin²θ

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

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

= 1 -
(1)/(2)

=
(1)/(2)

User Salomon
by
3.1k points
15 votes
15 votes

Answer:

√3/2

Explanation:

p/h=1/2

Using Pythagoras Theorem

b=√3

cos=√3/2

cos20= √3/2*20

= 10√3

User Lightalex
by
2.9k points
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