### Home > PC3 > Chapter 8 > Lesson 8.2.1 > Problem 8-68

8-68.

Consider the graphs of

*y*= sin(*x*+*π*) and*y*= –sin(*x*). Homework Help ✎Sketch both graphs on separate axes. What do you notice?

Sketch the graph of

*y*= cos(*x*+*π*). What is it equivalent to?Use the unit circle to explain why adding

*π*to the angle*x*reverses the sign of the*x*- and*y*-coordinates.

The first curve is shifted left *π* units.

The second curve is reflected vertically.

Look at the equations of the curves and the hint in part (a).