I=∫01(2x3−3x2−x+1)31dx
Using ∫02af(x)dx=0 whenf(2a−x)=−f(x)
Now, finding f(1−x) we get,
⇒I=∫01(2(1−x)3−3(1−x)2−(1−x)+1)31dx
⇒I=∫01(2(1−x3−3x+3x2)−3(1+x2−2x)2−(1−x)+1)31dx
⇒I=∫01(2−2x3−6x+6x2−3−3x2+6x−1+x+1)31dx
⇒I=∫01(−2x3+3x2+x−1)31dx
⇒I=−I
⇒f(1−x)=−f(x)
∴I=0