determine the value of cos (-pi/2)
The value of cos (-pi/2) is 0.
To determine the value of cos (-π/2), follow these steps:
Step 1: Recall the unit circle. The cosine function represents the x-coordinate of a point on the unit circle.
Step 2: Understand the angle measure. In trigonometry, angles are measured counterclockwise from the positive x-axis. So, -π/2 represents an angle that starts from the positive x-axis and rotates clockwise by π/2 radians.
Step 3: Identify the reference angle. The reference angle is the positive acute angle formed between the terminal side of the angle and the x-axis. In this case, the reference angle is π/2 radians.
Step 4: Determine the cosine value. In the unit circle, the x-coordinate at a reference angle of π/2 is 0. Therefore, cos(π/2) = 0.
Step 5: Account for the negative sign. Since the angle -π/2 is in the fourth quadrant where cosine values are negative, the value of cos(-π/2) is -0, which simplifies to 0.
Therefore, the value of cos(-π/2) is 0.