Question

Which of the following is a solution to 4sin^2x – 1 = 0?
A.30
B.60
C.90
D.120

Answer 1

do you know what the value of sin30, sin60, sin90, and sin120 ?

Answer 2

sin30=\[\sqrt{3}\div2\], sin60=1/2, sin90=0, sin120=-1/2

Answer 3

huh ? i knowed that is for cos values :)

Answer 4

sorrry i confused myself its sin30=1/2, sin60=\[\sqrt{3}\div2\],sin90=1, and sin120= the same for sin60

Answer 5

yes, that's look better :)
so, just check one by one in your answer choice.

example : (this is for wrong answer, let it is C)
4sin^2x – 1 = 0
4sin^2(90) – 1 = 0
4(1)^2 - 1 = 0
4 - 1 = 0
3 = 0
LHS not equal with RHS

Answer 6

thanks

Answer 7

welcome :)