Question

Which of the following is NOT equal to sin pi/3

A) sin 2pi/3
B) cos pi/6
C) cos 11pi/6
D) sin 4pi/3

Answer 1

Answer:

D)  $sin(\frac{4\pi }{3} ) = sin(\pi +\frac{\pi }{3} ) = -sin\frac{\pi }{3}$

Step-by-step explanation:

A)

$sin(\frac{2\pi }{3} ) = sin ( \pi - \frac{\pi }{3} ) = sin\frac{\pi }{3}$

B)

$cos (\frac{\pi }{6} ) = cos ( \frac{\pi }{2} - \frac{\pi }{3} ) = sin(\frac{\pi }{3})$

C)

$cos (\frac{11\pi }{6} ) = cos ( \frac{3\pi }{2} + \frac{\pi }{3} ) = sin(\frac{\pi }{3})$

D)

 $sin(\frac{4\pi }{3} ) = sin(\pi +\frac{\pi }{3} ) = -sin\frac{\pi }{3}$