suppose cos(A) = 4/5. use the trig identity sin^2(A)+cos^2(A)=1 to find sin(A) in quadrant IV. round to the ten-thousandth.

a. -0.3954
b. -0.6000
c. 0.6485
d. 0.4500

Respuesta :

In quadrant IV, [tex]\sin(A)[/tex] is negative. So

[tex]\sin^2(A) + \cos^2(A) = 1 \implies \sin(A) = -\sqrt{1-\cos^2(A)} = -\dfrac35 = \boxed{-0.6000}[/tex]