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If \int_0^x f(t)dt = x^2 + \int_x^1t^2f(t)dt, then f\left(\frac{1}{2} \right ) is:

  • Option 1)

    \frac{6}{25}

  • Option 2)

    \frac{4}{5}

  • Option 3)

    \frac{24}{25}

  • Option 4)

    \frac{18}{25}

Answers (1)

best_answer

 

Derivative at a point -

The value of  f'(x) obtained by putting  x = a is called the derivative of  f(x) at  x = a  and it is denoted by  f'(a)  or  

\frac{dy}{dx}     at  x = a.

-

 

 

Algebraic functions -

\frac{d}{dx}(x^{n})=nx^{n-1}

\frac{d}{dx}(\frac{1}{f(x)})^{n}=\frac{-n}{(f(x))^{n+1}}.\frac{d}{dx}f(x)......and\:so\:on

-

 

 

Chain Rule for differentiation (indirect) -

Let  y = f(x)  is not in standard form then 

\frac{dy}{dx}=\frac{dy}{du}\times \frac{du}{dx}

ex:\:\:y=sin(ax+b)

Let\:\;u=(ax+b)

then\:\:y=sin \:u

so\:\:\frac{dy}{du}=cos \:u\:\:and\:\:\frac{du}{dx}=a

\therefore \frac{dy}{dx}=\frac{dy}{du}\times \frac{du}{dx}=a\:cos \:u

=a\:cos(ax+b)

 

- wherein

Where\;\:y=f(u)\:\;and\;\;u=f(x)

 

\int_{0}^{x}f(t)dt=x^{2}+\int_{x}^{1}t^{2}f(t)dt

Differentiate wrt 'x'

f(x)=2x+0-x^{2}f(x)

f(x)=\frac{2x}{x^{2}+1}

f{}'(x)=\frac{(1+x^{2})2-(2x)(2x)}{(x^{2}+1)^{2}}

           =\frac{2x^{2}-4x^{2}+2}{(x^{2}+1)^{2}}

f{}'(\frac{1}{2})=\frac{24}{25}

 

 

 

 


Option 1)

\frac{6}{25}

Option 2)

\frac{4}{5}

Option 3)

\frac{24}{25}

Option 4)

\frac{18}{25}

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