Answer
$sin\theta = -\frac{4}{5}$, $cos\theta = \frac{3}{5}$
Work Step by Step
For point (3, -4), it is in the 4th quadrant, the absolute value (modulus) is $\sqrt{3^2 + (-4)^2} = 5$, hence,
$sin\theta = -\frac{4}{5}$ and $cos\theta = \frac{3}{5}$
