Evaluate the indefinite integral. (Enter your answer in terms of cos function.)

http://www.webassign.net/cgi-bin/sym...pi%20t%29%20dt

so far i have:

u = 4 t

du = dt

1/ du = dt

once you subsitute it all back in i get a final answer of:

(1/ )(cos4 t)+c

but this is not correct....

where is my mistake?