Answer:
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 = ± [tex]\sqrt{0.395}[/tex] = ± 0.628
Hence a possible value for sinΘ is 0.63 ( 2 dec. places )
