Question

d trig graphs
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date:
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correct answer next to the problem number.

1. evaluate $sec 90^{\circ}$.

a) undefined b) 0 c) -1 d) 1

Explanation:

Step1: Recall secant definition

$\sec\theta = \frac{1}{\cos\theta}$

Step2: Substitute $\theta=90^\circ$

$\sec90^\circ = \frac{1}{\cos90^\circ}$

Step3: Evaluate $\cos90^\circ$

$\cos90^\circ = 0$

Step4: Analyze the expression

$\sec90^\circ = \frac{1}{0}$, division by zero is undefined.

Answer:

A) undefined