Question 640628
recall:

The {{{b}}} in both of the graph types

    {{{y = a* sin bx}}}
    {{{y = a *cos bx}}}

affects the period (or wavelength) of the graph. As b gets larger, the period decreases.
The period is the distance (or time) that it takes for the {{{sine}}} or {{{cosine}}} curve to begin repeating again.

The period is given by:

    {{{Period=2pi/b}}}

so, the period in {{{y= 400 *cos 5*pi*x}}} where {{{a=400}}}, {{{b=5*pi}}} will be

{{{Period=2*pi/5*pi}}}

{{{Period=2*cross(pi)/5*cross(pi)}}}


{{{Period=2/5}}}