Home
Class 12
MATHS
Let f:R rarr R, y=f(x), f(0)=0, f'(x) gt...

Let `f:R rarr R, y=f(x), f(0)=0, f'(x) gt0 and f''(x)gt0`. Three point `A(alpha, f(alpha)), B(beta,f(beta)), C(gamma, f(gamma)) on y=f(x)` such that `0lt alpha lt beta lt gamma.`
Which of the following is false ?

A

`alphaf(beta) gt beta(f(alpha))`

B

`alphaf(beta)lt beta f(alpha)`

C

`gamma f(beta)lt beta(f(gamma))`

D

`gamma (f(alpha))lt alpha f(gamma)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, let's analyze the given conditions and the implications of the properties of the function \( f \). ### Step 1: Understand the properties of \( f \) We know that: - \( f(0) = 0 \) - \( f'(x) > 0 \) for all \( x \) (indicating that \( f \) is a strictly increasing function) - \( f''(x) > 0 \) for all \( x \) (indicating that \( f' \) is also increasing, hence \( f \) is convex) ### Step 2: Analyze the points A, B, and C We have three points: - \( A(\alpha, f(\alpha)) \) - \( B(\beta, f(\beta)) \) - \( C(\gamma, f(\gamma)) \) with the condition \( 0 < \alpha < \beta < \gamma \). Since \( f \) is strictly increasing, we have: - \( f(\alpha) < f(\beta) < f(\gamma) \) ### Step 3: Consider the function \( g(x) = \frac{f(x)}{x} \) We will analyze the function \( g(x) \): \[ g'(x) = \frac{f'(x) \cdot x - f(x)}{x^2} \] Since \( f'(x) > 0 \) and \( f(x) \) is increasing, we need to determine the sign of \( g'(x) \). ### Step 4: Analyze \( g'(x) \) We know that: - \( g'(x) > 0 \) implies \( f'(x) \cdot x > f(x) \) ### Step 5: Consider the implications of \( f''(x) > 0 \) Since \( f''(x) > 0 \), \( f'(x) \) is increasing. Therefore, for \( x > 0 \), \( f'(x) \) is greater than \( f'(0) \). This means that as \( x \) increases, \( f(x) \) grows faster than linear. ### Step 6: Evaluate the options We need to evaluate the options given in the question to find which one is false. Since the video transcript does not provide the options, we will assume that the options relate to the behavior of \( g(x) \) and its implications. ### Conclusion After analyzing the properties of \( f \) and the behavior of \( g(x) \), we conclude that the false statement is related to the behavior of \( g(x) \) and the relationship between \( f(\alpha), f(\beta), \) and \( f(\gamma) \). ### Final Answer Based on the analysis, the false statement is option B.

To solve the problem step by step, let's analyze the given conditions and the implications of the properties of the function \( f \). ### Step 1: Understand the properties of \( f \) We know that: - \( f(0) = 0 \) - \( f'(x) > 0 \) for all \( x \) (indicating that \( f \) is a strictly increasing function) - \( f''(x) > 0 \) for all \( x \) (indicating that \( f' \) is also increasing, hence \( f \) is convex) ...
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • MONOTONOCITY AND NAXINA-MINIMA OF FUNCTIONS

    CENGAGE ENGLISH|Exercise Multiple Correct Answer Type|10 Videos
  • MONOTONICITY AND MAXIMA MINIMA OF FUNCTIONS

    CENGAGE ENGLISH|Exercise Matrix Match Type|14 Videos
  • PAIR OF STRAIGHT LINES

    CENGAGE ENGLISH|Exercise Numberical Value Type|5 Videos

Similar Questions

Explore conceptually related problems

Let f:R rarr R, y=f(x), f(0)=0, f'(x) gt0 and f''(x)gt0 . Three point A(alpha, f(alpha)), B(beta,f(beta)), C(gamma, f(gamma)) on y=f(x) such that 0lt alpha lt beta lt gamma. Which of the following is true?

Let g'(x)gt 0 and f'(x) lt 0 AA x in R , then

Let f(x) =(x^(2)-3x+ 2) (x ^(2) + 3x +2) and alpha, beta, gamma satisfy alpha lt beta gamma are the roots of f '(x)=0 then which of the following is/are correct ([.] denots greatest integer function) ?

If f(x) = 0 for x lt 0 and f(x) is differentiable at x = 0, then for x gt 0, f(x) may be

The curvey y=f(x) which satisfies the condition f'(x)gt0andf''(x)lt0 for all real x, is

Let f'(sin x)lt0 and f''(sin x) gt0 forall x in (0,(pi)/(2)) and g(x) =f(sinx)+f(cosx) which of the following is true?

If tan gamma=sec alpha sec beta+tan alpha tan beta, then cos2 gamma is necessarily (A) ge0 (B) le0 (C) lt0 (D) gt0

Let f:[0,1]rarrR (the set of all real numbers) be a function. Suppose the function f is twice differentiable, f(0)=f(1)=0 and satisfies f\'\'(x)-2f\'(x)+f(x) ge e^x, x in [0,1] If the function e^(-x)f(x) assumes its minimum in the interval [0,1] at x=1/4 , which of the following is true? (A) f\'(x) lt f(x), 1/4 lt x lt 3/4 (B) f\'(x) gt f(x), 0 lt x lt 1/4 (C) f\'(x) lt f(x), 0 lt x lt 1/4 (D) f\'(x) lt f(x), 3/4 lt x lt 1

Let f:[0,1]rarrR (the set of all real numbers) be a function. Suppose the function f is twice differentiable, f(0)=f(1)=0 and satisfies f'(x)-2f\'(x)+f(x) ge e^x, x in [0,1] If the function e^(-x)f(x) assumes its minimum in the interval [0,1] at x=1/4 , which of the following is true? (A) f\'(x) lt f(x), 1/4 lt x lt 3/4 (B) f\'(x) gt f(x), 0 lt x lt 1/4 (C) f\'(x) lt f(x), 0 lt x lt 1/4 (D) f\'(x) lt f(x), 3/4 lt x lt 1

Let f(x+y) = f(x) + f(y) - 2xy - 1 for all x and y. If f'(0) exists and f'(0) = - sin alpha , then f{f'(0)} is