推 chat543:感謝^^~125.229.192.196 07/06 21:18
※ 引述《chat543 (小ㄐ)》之銘言：
: Find a function f and a constant c such that
: x
: ∫ tf(t)dt = sinx - xcosx -1/2x^2 , for all x.
: c
x=c sinc-c*cosc - 0.5 c^2 = 0
=> c = 0
xf(x) = cosx - cosx + xsinx - x
=>f(x) = [xsinx - x]/x
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