suppose sin(A) = 1/4. use the trig identity sin^2(A)+cos^2(A)=1 to find cos(A) in quadrant II. around to ten-thousandth.

a. 0.1397
b. 0.4630
c. -0.8572
d. -0.9682

Respuesta :

In quadrant II, [tex]\cos(A)[/tex] will be negative. So

[tex]\sin^2(A) + \cos^2(A) = 1 \implies \cos(A) = -\sqrt{1 - \sin^2(A)} = -\dfrac{\sqrt{15}}4 \approx \boxed{-0.9682}[/tex]