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).