Chapter 9.1, Problem 59E

(a)

To determine

To graph: The functions $y_1=\frac{2}{\pi }\cos x,y_3=\frac{2}{\pi }\cos x+\frac{2}{3\pi }\cos 3x$ and $y_5=\frac{2}{\pi }\cos x+\frac{2}{3\pi }\cos 3x+\frac{2}{5\pi }\cos 5x$ in a window with $-7\le x\le 7\text{ and}-1.5\le y\le 1.5$.

(b)

To determine

To graph: The function $y_{11}$ derived from the pattern established above in a window with $-7\le x\le 7\text{ and}-1.5\le y\le 1.5$.

(c)

To determine

To calculate: The value of the function $y_{11}$ derived in part (b) to approximate a sawtooth wave with amplitude of three times and a period of $4\pi$.