NBT NBT Mathematics: Trigonometry 2

Question 1

What is the value of tan 45°?

Accepted Answer

1

Answer

At 45°, sin 45° = cos 45° = 1/√2, so tan 45° = sin/cos = 1.

Question 2

The amplitude of y = 3sin(x) is:

Accepted Answer

3

Answer

The amplitude of y = A sin(x) is |A|; here A = 3, so the amplitude is 3.

Question 3

If cos θ = −√3/2 and 180° < θ < 270°, what is θ?

Accepted Answer

210°

Answer

cos 30° = √3/2, so the reference angle is 30°; in Quadrant III, θ = 180° + 30° = 210°.

Question 4

Which identity is correct?

Accepted Answer

1 + cot²θ = cosec²θ

Answer

The identity 1 + cot²θ = cosec²θ is derived from dividing sin²θ + cos²θ = 1 by sin²θ.

Question 5

On the unit circle, the point (0, −1) corresponds to which angle?

Accepted Answer

270°

Answer

The point (0, −1) on the unit circle corresponds to 270° (or 3π/2 radians).

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