Mathematics
Senior High

積分得意な方教えてください!!!!!(>_<)

Answers

(1)
aを定数とおく。

∫[x↑a↓]f(t)dt
xで微分するとf(x)

f(x)=2x^3-∫[x↑-1↓](3t^2+at+b)dtより
f'(x)=6x^2-(3x^2+ax+b)
f'(1)=6-(3+a+b)=0
f'(2)=24-(12+2a+b)=5
より、
a+b=3
2a+b=7
∴a=4,b=-1
(2)
f(x)=2x^3-∫[-1→x](3t^2+4t-1)dt
=2x^3-[t^3+2t^2-t]_-1→x
=2x^3-(x^3+2x^2-x)+(-1+2+1)
=x^3-2x^2+x+2

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