Their is a TYPO on page 376, in Appendix C of the Reserve Readings assigned on calculus review. Equation C.7 is shown as:

f(X) = a sin(bX + c)

The equation should be:

f(X) = a sin[b(X + c)]

In figure C.9, the graph of the function:

f(X) = 3sin(X/2 - PI/2)

can be written as:

f(X) = 3sin[1/2(X - PI)]

Thus, the function f(X) = 3sin[1/2(X + PI)] will be shifted by the value of PI to the right relative to the graph of function f(X) = 3sin[X/2] = 3sin[1/2(X)] shown in figure C.8.

Bottom line the text in the book is correct, but their expression of equation C.7 is incorrect.