Home
Class 11
MATHS
If for the function 'f', given by : f(...

If for the function 'f', given by :
`f(x)=kx^(2)+7x+4, f^(')(5)=97`, find 'k'.

Text Solution

AI Generated Solution

The correct Answer is:
To find the value of \( k \) for the function \( f(x) = kx^2 + 7x + 4 \) given that \( f'(5) = 97 \), we will follow these steps: ### Step 1: Find the derivative of the function The function is given as: \[ f(x) = kx^2 + 7x + 4 \] To find the derivative \( f'(x) \), we differentiate each term: \[ f'(x) = \frac{d}{dx}(kx^2) + \frac{d}{dx}(7x) + \frac{d}{dx}(4) \] Using the power rule: \[ f'(x) = 2kx + 7 + 0 = 2kx + 7 \] ### Step 2: Substitute \( x = 5 \) into the derivative We know that \( f'(5) = 97 \). So we substitute \( x = 5 \) into the derivative: \[ f'(5) = 2k(5) + 7 \] This simplifies to: \[ f'(5) = 10k + 7 \] ### Step 3: Set up the equation using the given information Since we know \( f'(5) = 97 \), we can set up the equation: \[ 10k + 7 = 97 \] ### Step 4: Solve for \( k \) Now we will solve for \( k \): \[ 10k = 97 - 7 \] \[ 10k = 90 \] \[ k = \frac{90}{10} = 9 \] ### Conclusion Thus, the value of \( k \) is: \[ \boxed{9} \]
Promotional Banner

Topper's Solved these Questions

  • LIMITS AND DERIVATIVES

    MODERN PUBLICATION|Exercise EXERCISE 13 (a)|57 Videos
  • LIMITS AND DERIVATIVES

    MODERN PUBLICATION|Exercise EXERCISE 13 (b)|59 Videos
  • LIMITS AND DERIVATIVES

    MODERN PUBLICATION|Exercise ILLUSTRATIVE EXAMPLES|16 Videos
  • INTRODUCTION TO THREE DIMENSIONAL GEOMETRY

    MODERN PUBLICATION|Exercise CHAPTER TEST|12 Videos
  • LINEAR INEQUATIONS

    MODERN PUBLICATION|Exercise CHAPTER TEST|12 Videos

Similar Questions

Explore conceptually related problems

Domain of the function f given by f(x) = 2-|x-5| is

For the function f given by f(x)=x^(2)-6x+8, prove that f'(5)-3f'(2)=f'(8)

A function f is defined by f(x) = x^(2) + 1 . Find f(0), f(5), f(10).

Let f:R rarr R be a function given by f(x)=x^(2)+1. Find: f^(-1){-5}

For the function f,f(x)=x^(2)-4x+7, show that f'(5)=2f'((7)/(2))

Find f'(2) and f'(5) when f(x)=x^(2)+7x+4

Find the value of k, if the function f given by : {:(f(x)=(1-tanx)/(1-sqrt2sinx)",", "for" x nepi/4),(=k/2",","for"x=pi/4):} is continous at x =pi/4*