What is a possible value of sin theta when cos2theta= 0.21

a. 0.32
b. 0.37
c. 0.63
d. 0.68

will give the

c

Step-by-step explanation:

Using the trigonometric identity

• cos2x = 1 - 2sin²x , then

1 - 2sin²Θ = cos2Θ = 0.21 ( subtract 1 from both sides )

- 2sin²Θ = - 0.79 ( divide both sides by - 2 )

sin²Θ = 0.395 ( take the square root of both sides

sinΘ = ± = ± 0.628

Hence a possible value for sinΘ is 0.63 ( 2 dec. places )

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