Solveeit Logo

Question

Question: If \(f(x) = x^{n},\) then the value of \(f(1) - \frac{f'(1)}{1!} + \frac{f''(1)}{2!} - \frac{f'''(1...

If f(x)=xn,f(x) = x^{n}, then the value of

f(1)f(1)1!+f(1)2!f(1)3!+......+(1)nfn(1)n!f(1) - \frac{f'(1)}{1!} + \frac{f''(1)}{2!} - \frac{f'''(1)}{3!} + ...... + \frac{( - 1)^{n}f^{n}(1)}{n!} is

A

2n2^{n}

B

2n12^{n - 1}

C

0

D

1

Answer

0

Explanation

Solution

f(x)=xnf(1)=1f(x) = x^{n} \Rightarrow f(1) = 1, f(x)=nxn1f(1)=nf^{'}(x) = nx^{n - 1} \Rightarrow f^{'}(1) = n

f(x)=n(n1)xn2f(1)=n(n1)f^{''}(x) = n(n - 1)x^{n - 2} \Rightarrow f^{''}(1) = n(n - 1) …..

fn(x)=n!fn(1)=n!f^{n}(x) = n! \Rightarrow f^{n}(1) = n!, f(1)f(1)1!+f(1)2!......+(1)nfn(1)n!\therefore f(1) - \frac{f^{'}(1)}{1!} + \frac{f^{''}(1)}{2!}...... + \frac{( - 1)^{n}f^{n}(1)}{n!}

=nC0nC1+nC2nC3+......+(1)nnCn=0=^{n} ⥂ C_{0} -^{n} ⥂ C_{1} +^{n} ⥂ C_{2} -^{n} ⥂ C_{3} + ...... + ( - 1{)^{n}}^{n} ⥂ C_{n} = 0.