Trigonometry Practice Test 1

tan θ = – 4/3
⇒ θ lies in 2nd or 4th quadrant.
∴ sin θ is positive or negative according as θ lie in 2nd or 4th quadrant respectively, i.e., sin θ may be positive or negative.
Now $\sin \mathit{\theta }=\tan \frac{\mathit{\theta }}{\sqrt{\left(1+{\tan }^2\mathit{\theta }\right)}}=\frac{4}{5}$
Hence sin θ = – 4/5 or 4/5.