Question

Which of the following statement is not true about sin theta, where theta is 2π/3 radians.

a) it has the same value as sin(8π/3)
b) it has the same value as sin30°
c) it has a positive value
d) it has a negative value​

Answer 1

Explanation:

2pi/3 is the same thing as 2pi/3 * 180/pi = 120 degrees

From your choices, we know that it is either c or d.

sin(120) is in the 2nd quadrant, so the x is negative and the y is positive. Remember that sin corresponds to the y value, so it is positive. Therefore option (d) is not true.