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If f(x)=|{:(x^(n),sinx,cosx),(n!,"sin"(n...

If `f(x)=|{:(x^(n),sinx,cosx),(n!,"sin"(npi)/(2),"cos"(npi)/(2)),(a,a^(2),a^(3)):}|`, then the value of `(d^(n))/(dx^(n))(f(x))" at "x=0" for "n=2m+1` is

A

-1

B

0

C

1

D

independent of a

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The correct Answer is:
To solve the problem, we need to evaluate the \( n \)-th derivative of the function \( f(x) \) at \( x = 0 \) where \( n = 2m + 1 \). The function \( f(x) \) is defined as a determinant involving \( x^n \), \( \sin x \), \( \cos x \), and some constants. ### Step-by-step Solution: 1. **Understanding the Function**: The function is given as: \[ f(x) = \begin{vmatrix} x^n & \sin x & \cos x \\ n! & \sin\left(\frac{n\pi}{2}\right) & \cos\left(\frac{n\pi}{2}\right) \\ a & a^2 & a^3 \end{vmatrix} \] 2. **Differentiating the Determinant**: To find \( \frac{d^n}{dx^n} f(x) \) at \( x = 0 \), we can use the property of determinants. We differentiate the first row with respect to \( x \): - The derivative of \( x^n \) is \( n x^{n-1} \). - The derivative of \( \sin x \) is \( \cos x \). - The derivative of \( \cos x \) is \( -\sin x \). Thus, the first derivative of the determinant becomes: \[ f'(x) = \begin{vmatrix} n x^{n-1} & \cos x & -\sin x \\ n! & \sin\left(\frac{n\pi}{2}\right) & \cos\left(\frac{n\pi}{2}\right) \\ a & a^2 & a^3 \end{vmatrix} \] 3. **Evaluating at \( x = 0 \)**: Now, we substitute \( x = 0 \): - \( \sin(0) = 0 \) - \( \cos(0) = 1 \) - The determinant simplifies to: \[ f(0) = \begin{vmatrix} 0 & 0 & 1 \\ n! & \sin\left(\frac{n\pi}{2}\right) & \cos\left(\frac{n\pi}{2}\right) \\ a & a^2 & a^3 \end{vmatrix} \] Since the first row has a zero, the determinant evaluates to zero. 4. **Higher Derivatives**: Continuing this process, we find that each time we differentiate, if we have a row of zeros, the determinant remains zero. Thus, for any odd \( n \) (where \( n = 2m + 1 \)), the \( n \)-th derivative evaluated at \( x = 0 \) will also yield zero. 5. **Conclusion**: Therefore, the value of \( \frac{d^n}{dx^n} f(x) \) at \( x = 0 \) for \( n = 2m + 1 \) is: \[ \boxed{0} \]

To solve the problem, we need to evaluate the \( n \)-th derivative of the function \( f(x) \) at \( x = 0 \) where \( n = 2m + 1 \). The function \( f(x) \) is defined as a determinant involving \( x^n \), \( \sin x \), \( \cos x \), and some constants. ### Step-by-step Solution: 1. **Understanding the Function**: The function is given as: \[ f(x) = \begin{vmatrix} ...
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OBJECTIVE RD SHARMA-DIFFERENTIATION-Section I - Solved Mcqs
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