Question:medium

If $f(x)=x^2+g^{\prime}(1) x+g^{\prime \prime}(2)$ and $g(x)=f(1) x^2+x f^{\prime}(x)+f^{\prime \prime}(x)$, then the value of $f(4)-g(4)$ is equal to ______

Updated On: Mar 31, 2026
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Correct Answer: 14

Solution and Explanation

Computing derivatives: \[ f'(x) = 2x + g'(1), \quad f''(x) = 2 \] Solving for \( g(x) \), \[ g(x) = f(1)x^2 + x[2x + g'(1)] + 2 \] \[ g'(x) = 2f(1)x + 4x + g'(1) \] \[ g''(x) = 2f(1) + 4 \] Setting boundary conditions: \[ f(1) = -2, \quad g'(1) = -3 \] \[ f(x) = x^2 - 3x \] \[ g(x) = -3x + 2 \] \[ f(4) - g(4) = 14 \]

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