Question

Graph the function. y = cos (x + pi/2)

Answer 1

First write out the equation

$\begin{gathered} y\text{ = cos ( x + }\frac{\pi}{2}) \\ \pi=180^0 \\ y\text{ = cos (x + 90)} \\ \end{gathered}$

for

$\begin{gathered} \theta\text{ = 0 y = cos(90) = 0} \\ \theta\text{ = 30 y = cos(120) = -0.5} \\ \theta\text{ = 60 y = cos 150 = - 0.866} \\ \theta\text{ = 90 y = cos 180 = -1} \\ \theta\text{ = 120 y = cos 210 = -0.866} \end{gathered}$