Question

Find a cosine function whose period is 7.

Answer 1

periodic function is a special type of function in which, function returning to the same value at regular intervals. for any function y = f(x) , T will be period only when f(x) = f(x + T).

we know , if period of function y = f(x) is T then period of function y = f(ax ± b) will be T/|a|

we have to find a cosine function whose period is 7. we know, period of cosx = 2π .
so, coefficient of x in such a way that its period will be 7.
if we let coefficient of x is A
then, 2π/A = 7
A = 2π/7

hence, cosine function should be f(x) = cos(2πx/7)

Answer 2

Answer:

period of cos is 2 pi

so 2pi/A = 7

A = 2pi/7