f(t)=cos(πt/4)

finding velocity i got

-π/4sin(πt/4)

then i had to find velocity after 3 sec which is v'(3)=-π/4sin(π(3)/4) = -π/4sin(π√2/2)

(-π) (π√2)/4 x 2 = -1/8√2 ft/s

i now have to find when the particle is at rest? how would you do this without graphing?

3 answers

at rest means velocity = 0

right?
right
the answer is 0, 4, and 8 how do i get that from the equation?