The answer is 1/4 = 2pi * 1/T, so T = 4*2pi = 8pi
so it is <span>d.8pi</span>
Expression is equivalent to the given expression 13x−29xthat could be simplified by just substracting it13x − 29x = -16x but it is not in the choices
13x − 29xfactor out, so it will be the same with choice
x(13 - 29)

Let

so that

. Then the integral becomes
His model is incorrect because 20 x 7 is not 14, it is 140. If he had 140 instead of 14, he would have been correct.
I haven't done division like that in a long time, so this is what I think it will look like. I didn't add other work (multiplying 4 with #'s) but you can if you have to
Acute angles because they are less then 90 degrees which is a right angle.