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Find the terminal point on the unit circle determined by −13π/4 radians

a) Terminal point: (√2/2, -√2/2)
b) Terminal point: (-√2/2, -√2/2)
c) Terminal point: (-√2/2, √2/2)
d) Terminal point: (√2/2, √2/2)

1 Answer

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Final answer:

The terminal point on the unit circle determined by −13π/4 radians is (-√2/2, √2/2), corresponding to the coordinate in the second quadrant for the angle 3π/4.

Step-by-step explanation:

The student has asked to find the terminal point on the unit circle for the angle −13π/4 radians. To find this, we first need to reduce the angle to a coterminal angle between 0 and 2π radians. Since the full rotation in radians is 2π (which equals 8π/4), we can add this to −13π/4 until we get an equivalent positive angle that falls within the desired range.

−13π/4 + 2(8π/4) = −13π/4 + 16π/4 = 3π/4

This reduced angle corresponds to a point in the second quadrant on the unit circle where both sine and cosine are negative. The terminal point for 3π/4 on the unit circle is (√2/2, √2/2), but since it is in the second quadrant, the x-coordinate (cosine) should be negative. Therefore, the terminal point is (√2/2, √2/2).

User Lauren Van Sloun
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