Posted by LILY on .
If f(x)= ∫(21,x) t^5 dt then f'(x).
my answer was 1/6 (21^6x^6) it said it's wrong.

college Calculus Help! 
Reiny,
You must be Mily from below.
same thing as before
∫ t^5 dt from t=21 to t=x
= (1/6)t^6 from t21 to t=x
= (1/6)x^6  (1/6)(21)^6
= (1/6)(x^6  21^6) 
college Calculus Help! 
LILY,
what about f ' (x)?
i did with (1/6)(x^621^6) but its wrong
f(x)=∫(21,x) t^5
f'(x)= x^5
i font know 
college Calculus Help! 
LILY,
but thanks

college Calculus Help! 
LILY,
i got it, it correct answer is f'(x)=x^5.