How do you find the period and amplitude of #y=2/3cos((pix)/10)#?

1 Answer
Mar 29, 2017

amplitude is 2/3
period is 20

Explanation:

#y=alpha*cos(x)# period is given as #(2pi)# and amplitude is #alpha#
for #y=cos(ax)#, period is given as #(2pi)/a#
here, y=#(2/3)cos(pi/10)x#
so period is #(2pi)/(((pi)/10))=20#

also, amplitude is #2/3#, because the maximum deviation of curve from the mean is #2/3# at cos#((pix)/10) # = 1

graph{(2/3)cos((pix)/10)[-10, 10, -5, 5]}