Question

5 multiple choice 1 point evaluate the trigonometric function of the given quadrantal angle. cos 1620° 1 0 -1 undefined

Explanation:

Step1: Find the coterminal angle

To find a coterminal angle of \(1620^{\circ}\), we use the formula \(\theta - 360^{\circ}n\) (where \(n\) is an integer).
Let \(n = 4\), then \(1620^{\circ}-360^{\circ}\times4=1620^{\circ} - 1440^{\circ}=180^{\circ}\)

Step2: Evaluate the cosine function

We know that \(\cos\theta\) for \(\theta = 180^{\circ}\) is given by the unit - circle definition. On the unit circle, for the angle \(\theta=180^{\circ}\) (the point \((- 1,0)\)), \(\cos\theta=x\) coordinate of the point on the unit circle. So, \(\cos180^{\circ}=-1\)

Answer:

\(-1\) (assuming the option with \(-1\) is the correct one among the given choices. If the options are labeled with symbols (e.g., A, B, C, D), and if the \(-1\) option is, say, option C, then the answer is C. Option Text with value \(-1\))