If x is a positive acute angle and cos x = radical3/4, what is the exact value of sin x?

Question

1) radical3/4
2) 3/5
3) radical13/4
4) 4/5

Answer 1

a=sqrt(3)
b=1
c=sqrt(4)
Since [sqrt(3)]^2+1^2=[sqrt(4)}^2
Therefore, sinx=1/sqrt(4)=1/2.

Answer 2

cos^2 (x) =3/4
sin^2(x) = 1 - cos^2(x)= 1-3/4 = .25
sin(x) = .5

Answer 3

3

cos = adj/hyp

4^2 = (sq rt 3)^2 + a^2

16 = 3 + a^2

a^2 = 13

a = sq rt 13

sin = sq rt 13 / 4

Answer 4

...if you mean cos(x)=SQRT(3/4) then sin(x)=0.5
otherwise its not one of those...