Trigonometric Functions Quiz
Grade 11 · Math · Quiz
Test your mastery of sine, cosine, tangent, the unit circle, identities, and graphing trig functions.
Questions
What is the exact value of sin(30 degrees)?
- sqrt(3)/2
- 1/2
- sqrt(2)/2
- 1
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Answer: 1/2
sin(30 degrees) = 1/2 is a standard unit circle value. The 30-60-90 triangle gives sides 1, sqrt(3), 2.
On the unit circle, at angle theta = 3pi/2, what are the coordinates (cos theta, sin theta)?
- (0, 1)
- (0, -1)
- (-1, 0)
- (1, 0)
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Answer: (0, -1)
At 3pi/2 (270 degrees), the point on the unit circle is (0, -1), so cos(3pi/2) = 0 and sin(3pi/2) = -1.
The period of the function y = sin(2x) is pi, which is half the period of y = sin(x).
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Answer: True
The period formula is T = 2pi divided by b. For y = sin(2x), b = 2, so T = 2pi/2 = pi.
Which identity is the Pythagorean Identity?
- sin(2 theta) = 2 sin(theta) cos(theta)
- sin^2(theta) + cos^2(theta) = 1
- tan(theta) = sin(theta) + cos(theta)
- cos(2 theta) = cos^2(theta) + sin^2(theta)
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Answer: sin^2(theta) + cos^2(theta) = 1
sin^2(theta) + cos^2(theta) = 1 is the fundamental Pythagorean Identity, derived from the unit circle equation x^2 + y^2 = 1.
The amplitude of y = -3cos(x) is:
- -3
- 3
- 1/3
- 6
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Answer: 3
Amplitude = |a| = |-3| = 3. The negative sign reflects the graph but does not change the amplitude.
tan(theta) is undefined whenever cos(theta) equals ___.
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Answer: 0
tan(theta) = sin(theta)/cos(theta), which is undefined when the denominator cos(theta) = 0 (at theta = pi/2, 3pi/2, etc.).
Which quadrant has both sine and cosine negative?
- Quadrant I
- Quadrant II
- Quadrant III
- Quadrant IV
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Answer: Quadrant III
In Quadrant III, x and y are both negative, so cos(theta) < 0 and sin(theta) < 0. Only tangent is positive there.
Using the double angle formula, sin(2 theta) when sin(theta) = 3/5 and theta is in Quadrant I equals:
- 6/25
- 24/25
- 7/25
- 12/25
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Answer: 24/25
sin(2 theta) = 2 sin(theta) cos(theta). With sin(theta) = 3/5 and cos(theta) = 4/5 (Q1, Pythagorean), sin(2 theta) = 2 times (3/5) times (4/5) = 24/25.
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