Question:

If \[ \int_0^1 (3x^2+2x+1)\,dx=k, \] then the value of \(k\) is

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For polynomial integrals, integrate each term separately and then substitute the upper and lower limits carefully. This avoids common arithmetic mistakes.
Updated On: Jun 10, 2026
  • \(2\)
  • \(3\)
  • \(4\)
  • \(5\)
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The Correct Option is B

Solution and Explanation

Concept: To evaluate a definite integral, first find the antiderivative and then apply the Fundamental Theorem of Calculus: \[ \int_a^b f(x)\,dx = F(b)-F(a), \] where \(F'(x)=f(x)\).

Step 1: Integrate the polynomial Given, \[ \int_0^1 (3x^2+2x+1)\,dx. \] Integrating term by term, \[ \int 3x^2\,dx=x^3, \] \[ \int 2x\,dx=x^2, \] \[ \int 1\,dx=x. \] Therefore, \[ \int (3x^2+2x+1)\,dx = x^3+x^2+x. \]

Step 2: Apply the limits \[ k = \left[x^3+x^2+x\right]_0^1. \] Substituting the upper limit: \[ 1^3+1^2+1 = 3. \] Substituting the lower limit: \[ 0^3+0^2+0 = 0. \] Hence, \[ k=3-0. \] \[ k=3. \] Therefore, \[ \boxed{3}. \]
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