Mark M. answered 04/28/21
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
The graph of y = √(36 - t2) is the upper semicircle with center (0,0) and radius 6, where -6 ≤ t ≤ 6.
So, ∫(from 0 to x) √(36 - t2)dt is the area of the portion of the right half of the semicircle (defined above) that lies between t = 0 and t = x. When x = 0, the value of the integral is also 0. When x = 6, the value of the integral is the area of the quarter circle, which is 36π/4 = 9π. So, the range is [0, 9π].
Sreeram K.
Thanks alot05/05/21