Question

which trig function is this? tan cos sin

Explanation:

Step1: Recall trigonometric function definitions

• $\sin\theta=\frac{\text{opposite}}{\text{hypotenuse}}$
• $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$
• $\tan\theta=\frac{\text{opposite}}{\text{adjacent}}$

Step2: Identify sides relative to the given angle

For the $20^{\circ}$ angle, the side of length $5$ is adjacent (next to the angle), and the hypotenuse is $12$.

Step3: Match with function definition

Since we have $\frac{\text{adjacent}}{\text{hypotenuse}}$, this matches the definition of $\cos\theta$.

Answer:

$\cos$