IB Maths AA

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The unit circle and circular functions practice questions — IB Maths AA

12 free multiple-choice problems on the unit circle and circular functions, ordered to match IB Maths AA difficulty, each with a full worked solution. No account needed — and there's a fresh problem set every day.

Problems & worked solutions

Problem #0555 International

Problem 1The unit circle and circular functions

The value of sin11π6\sin\dfrac{11\pi}{6} is:

Show answer & worked solution
  1. A. 12\dfrac{1}{2}
  2. B. 12-\dfrac{1}{2}✓ correct
  3. C. 32\dfrac{\sqrt{3}}{2}
  4. D. 32-\dfrac{\sqrt{3}}{2}

sin ⁣(2ππ6)=sinπ6=12\sin\!\left(2\pi - \dfrac{\pi}{6}\right) = -\sin\dfrac{\pi}{6} = -\dfrac{1}{2}.

Problem #0557 International

Problem 2The unit circle and circular functions

The point on the unit circle associated with x=7π4x = \dfrac{7\pi}{4} lies in:

Show answer & worked solution
  1. A. the first quadrant
  2. B. the second quadrant
  3. C. the third quadrant
  4. D. the fourth quadrant✓ correct

7π4 ⁣(3π2,2π)\dfrac{7\pi}{4} \in \!\left(\dfrac{3\pi}{2}, 2\pi\right), which is the fourth quadrant.

Problem #0559 International

Problem 3The unit circle and circular functions

The number of solutions of sinx=12\sin x = -\dfrac{1}{2} on [0,2π)[0, 2\pi) is:

Show answer & worked solution
  1. A. 11
  2. B. 22✓ correct
  3. C. 33
  4. D. 44

sinx=12\sin x = -\dfrac{1}{2} at x=7π6x = \dfrac{7\pi}{6} (Q3) and x=11π6x = \dfrac{11\pi}{6} (Q4). Two solutions on [0,2π)[0, 2\pi).

Problem #0558 International

Problem 4The unit circle and circular functions

The value of tan7π6\tan\dfrac{7\pi}{6} is:

Show answer & worked solution
  1. A. 13\dfrac{1}{\sqrt{3}}✓ correct
  2. B. 13-\dfrac{1}{\sqrt{3}}
  3. C. 3\sqrt{3}
  4. D. 3-\sqrt{3}

tan ⁣(π+π6)=tanπ6=13\tan\!\left(\pi + \dfrac{\pi}{6}\right) = \tan\dfrac{\pi}{6} = \dfrac{1}{\sqrt{3}}.

Problem #0556 International

Problem 5The unit circle and circular functions

The value of cos ⁣(π3)\cos\!\left(-\dfrac{\pi}{3}\right) is:

Show answer & worked solution
  1. A. 12\dfrac{1}{2}✓ correct
  2. B. 12-\dfrac{1}{2}
  3. C. 32\dfrac{\sqrt{3}}{2}
  4. D. 32-\dfrac{\sqrt{3}}{2}

cos ⁣(π3)=cosπ3=12\cos\!\left(-\dfrac{\pi}{3}\right) = \cos\dfrac{\pi}{3} = \dfrac{1}{2}.

Problem #0945 US SAT

Problem 6The unit circle and circular functions

The exact value of sin ⁣(π6)\sin\!\left(\dfrac{\pi}{6}\right) is:

Show answer & worked solution
  1. A. 12\dfrac{1}{2}✓ correct
  2. B. 22\dfrac{\sqrt{2}}{2}
  3. C. 32\dfrac{\sqrt{3}}{2}
  4. D. 11

π6=30\dfrac{\pi}{6} = 30^{\circ}, and sin30=12\sin 30^{\circ} = \dfrac{1}{2}.

Problem #0551 International

Problem 7The unit circle and circular functions

The value of sinπ6\sin\dfrac{\pi}{6} is:

Show answer & worked solution
  1. A. 12\dfrac{1}{2}✓ correct
  2. B. 22\dfrac{\sqrt{2}}{2}
  3. C. 32\dfrac{\sqrt{3}}{2}
  4. D. 11

A standard unit-circle value: sinπ6=12\sin\dfrac{\pi}{6} = \dfrac{1}{2}.

Problem #0554 International

Problem 8The unit circle and circular functions

For x=2π3x = \dfrac{2\pi}{3}, the sign of sinx\sin x is:

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  1. A. positive✓ correct
  2. B. negative
  3. C. zero
  4. D. undefined

In the second quadrant (π/2<x<π\pi/2 < x < \pi), sinx>0\sin x > 0.

Problem #0552 International

Problem 9The unit circle and circular functions

The value of cosπ4\cos\dfrac{\pi}{4} is:

Show answer & worked solution
  1. A. 12\dfrac{1}{2}
  2. B. 22\dfrac{\sqrt{2}}{2}✓ correct
  3. C. 32\dfrac{\sqrt{3}}{2}
  4. D. 11

cosπ4=sinπ4=22\cos\dfrac{\pi}{4} = \sin\dfrac{\pi}{4} = \dfrac{\sqrt{2}}{2}.

Problem #0553 International

Problem 10The unit circle and circular functions

The value of tanπ3\tan\dfrac{\pi}{3} is:

Show answer & worked solution
  1. A. 13\dfrac{1}{\sqrt{3}}
  2. B. 11
  3. C. 3\sqrt{3}✓ correct
  4. D. 32\dfrac{\sqrt{3}}{2}

tanπ3=sin(π/3)cos(π/3)=3/21/2=3\tan\dfrac{\pi}{3} = \dfrac{\sin(\pi/3)}{\cos(\pi/3)} = \dfrac{\sqrt{3}/2}{1/2} = \sqrt{3}.

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