3.8 Unit circle and trigonometric identities Quiz

1. What are the coordinates, to 3 s.f., of the point on the unit circle at $\theta=150^\circ$?

• A. $(0.866,\,0.5)$
• B. $(-0.866,\,0.5)$
• C. $(-0.5,\,0.866)$
• D. $(0.5,\,0.866)$

2. If $\cos\theta=0.6$ and $\theta$ is acute, what is $\tan\theta$?

• A. $\frac34$
• B. $\frac45$
• C. $\frac35$
• D. $\frac43$

3. In a triangle, $a=8$, $b=10$ and $A=35^\circ$. How many triangles fit this data?

• A. Two
• B. One
• C. None
• D. Infinitely many

4. The graph of $y=\cos\theta$ comes from which part of the point moving round the unit circle?

• A. Its $y$-coordinate
• B. The gradient of the radius
• C. Its $x$-coordinate
• D. The length of the radius

5. Solve $4\sin x=3$ for $0^\circ\le x\le180^\circ$.

• A. $48.6^\circ$ only
• B. $41.4^\circ$ and $138.6^\circ$
• C. $48.6^\circ$ and $228.6^\circ$
• D. $48.6^\circ$ and $131.4^\circ$