silemus.

31u-substitution integral

Evaluate ∫01x(1−x2)3 dx\displaystyle \int_0^1 x(1 - x^2)^3\,dx.

Substitute u = 1 − x², so x dx = −½du, and the limits flip from x in [0,1] to u in [1,0]. The integral becomes ½∫₀¹u³du = ½·(1/4) = 1/8.

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