Use a Graphing Utility to Select the Correct Graph Of y

question 104

Multiple Choice

Use a graphing utility to select the correct graph of $y _ { 1 }$ and $y _ { 2 }$ in the same viewing window.Use the graphs to determine whether $y _ { 1 } = y _ { 2 }$ .Explain your reasoning.
$y _ { 1 } = \cos ( x + 4 ) , y _ { 2 } = \cos x + \cos 4$