#2.)The voltage across a 10-ohm resistor is v(t) = 170 sin(377t) V. Determine the average power absorbed by the resistor.

here is what I have so far.

#1.) R=10ohms, V(t)=170sin(377t)v... therefore use ohms law to find I(t)=17sin(377t)

Pr=i(t)*v(t) = (17sin(377t))*(170sin(377t)) = 2890sin^2(377t)

so that would be answer F

#2.) not quite as easy. my book has this equation for average power...

where is T defined in this problem? is it 377? so would it be something like this?

if so how is that even computed? thanks