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← JEE Main 2026 · 4 Apr · Shift 2
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JEE Main 2026 · 4 Apr · Shift 2, Mathematics question 4

If α=1\alpha=1 and β=1+i2\beta=1+i\sqrt2, where i=−1i=\sqrt{-1} are two roots of the equation x3+ax2+bx+c=0x^3+ax^2+bx+c=0, a,b,c∈Ra,b,c\in\mathbb R, then ∫−11(x3+ax2+bx+c)dx\displaystyle\int_{-1}^1\left(x^3+ax^2+bx+c\right)dx is equal to:

Choose one option
Answer and worked solution

Official answer: C

Cubic. Real coefficients put the conjugate 1−i21-i\sqrt2 among the roots too:
(x−1)(x2−2x+3)=x3−3x2+5x−3.(x-1)(x^2-2x+3)=x^3-3x^2+5x-3.

Integral. On [−1,1][-1,1] the odd terms vanish:
∫−11(−3x2−3) dx=−2−6=−8.\int_{-1}^1(-3x^2-3)\,dx=-2-6=-8.

(C)