Q. Find the reference angle for a rotation of 89π.Answer:
Understand reference angle: Understand the concept of a reference angle. A reference angle is the acute angle formed by the terminal side of an angle in standard position and the x-axis. It is always between 0 and π/2 radians (or 0 and 90 degrees) and is positive.
Determine angle quadrant: Determine the quadrant in which the angle (9π)/8 radians lies.Since (9π)/8 is greater than π (which is equivalent to 4π/4) and less than 3π/2 (which is equivalent to 6π/4), the angle lies in the third quadrant.
Calculate equivalent angle: Calculate the equivalent angle in the first or fourth quadrant.To find the reference angle for an angle in the third quadrant, subtract π (4π/4) from the given angle.Reference angle = (9π)/8−π=(9π)/8−(8π)/8=π/8
Verify reference angle: Verify that the reference angle is in the correct range.The reference angle 8π is between 0 and 2π, which is the correct range for a reference angle.