Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202325 JanuaryEvening Shift
Exam
JEE Main
Year
2023
Date
25 January
Shift
Evening Shift
Subject
Mathematics
Chapter
Functions

JEE Main 2023 · 25 January · Evening Shift · Mathematics · Functions

Let f: ℝ → ℝ be a function defined by f(x) = _ m \ 2 ( x - x) + m -...

Let f:R→Rbeafunctiondefinedbyf: \mathbb{R} \to \mathbb{R} be a function defined byf\left(x\right) = \log_{\sqrt{m}}\left\{\sqrt{2}\left(\sin x - \cos x\right) + m - 2\right\},forsome, for somem,suchthattherangeof, such that the range offis[0,2]is \left[0, 2\right]. Then the value of mm is _____ .

Options

  1. A55
  2. B33
  3. C22
  4. D44

Correct answer

A. 55

Step-by-step solution

Given,

f:R→Rf: \mathbb{R} \to \mathbb{R} be a function defined by f(x)=log⁡m{2(sin⁡x−cos⁡x)+m−2}f\left(x\right) = \log_{\sqrt{m}}\left\{\sqrt{2}\left(\sin x - \cos x\right) + m - 2\right\}, for some mm,

Also given the range of ff is \left[0, 2\right],</p><p>Nowweknowthat,</p><p>,</p><p>Now we know that,</p><p>- \sqrt{2} \le \sin x - \cos x \le \sqrt{2}</p><p></p><p>⇒ - 2 \le \sqrt{2}\left(\sin x - \cos x\right) \le 2</p><p>(Assuming</p><p>(Assuming\sqrt{2}\left(\sin x - \cos x\right) = k)</p><p>)</p><p>⇒ - 2 \le k \le 2 \ldots \left(1\right)</p><p>Nowtakingfunction</p><p>Now taking functionf\left(x\right) = \log_{\sqrt{m}}\left(k + m - 2\right)</p><p>Given,</p><p>Given,0 \le f\left(x\right) \le 2</p><p></p><p>⇒ 0 \le \log_{\sqrt{m}}\left(k + m - 2\right) \le 2</p><p></p><p>⇒ 1 \le k + m - 2 \le m</p><p></p><p>⇒ - m + 3 \le k \le 2 \ldots \left(2\right)</p><p>Nowfromequations(1) and (2)</p><p>Now from equations \left(1\right) \text{ and } \left(2\right), we get

−m+3=−2- m + 3 = - 2

⇒m=5⇒ m = 5

Practice Functions on Quantrex Academy →

More from Functions

Let ℕ denote the set of all positive integers. Consider the sets A = \ 1, 2, 3, 4, 5\ and… JEE Advanced 2026Let f:(1,∞)→ℝ be a function defined as f(x) = (x-1)/(x+1) . Let f^ i+1 (x) = f(f^i(x))… JEE Main 2026Let f be a polynomial function such that _2(f(x)) = ( _2(2+(2)/(3)+(2)/(9)+…∞))·… JEE Main 2026Let f: ℝ arrow ℝ be defined as f(x) = (2x^2 - 3x + 2)/(3x^2 + x + 3) . Then f is : JEE Main 2026Let e be the base of natural logarithm and let f: \ 1, 2, 3, 4\ arrow \ 1, e, e^2, e^3\… JEE Main 2026Let f: R arrow R be a function such that f(x) + 3f((π)/(2) - x) = x , x ∈ R . Let the… JEE Main 2026The sum of all the integral values of p such that the equation 3 ^2 x + 12 x - 3 = p , x… JEE Main 2026Let A = \ 1, 2, 3, 4, 5, 6\ . The number of one-one functions f: A arrow A such that f(1)… JEE Main 2026For the function f:[1,∞) arrow [1,∞) defined by f(x)=(x-1)^4+1 , among the two… JEE Main 2026Let for some α ∈ ℝ , f:ℝarrowℝ be a function satisfying f(x+y)=f(x)+2y^2+y+α xy for all… JEE Main 2026Let [·] denote the greatest integer function. If the domain of the function f(x) = ^ -1… JEE Main 2026The number of functions f: \ 1, 2, 3, 4\ arrow \ a, b, c\ , which are not onto, is: JEE Main 2026If the domain of the function f(x) = _ (0.6) (|(2x-5)/(x^2-4)|) is (-∞, a] \ b\ [c, d)… JEE Main 2026Given below are two statements: Statement I: The function f: R arrow R defined by… JEE Main 2026The sum of all the elements in the range of f(x)=Sgn( x)+Sgn( x)+Sgn( x)+Sgn( x) , x ≠ n… JEE Main 2026If g(x)=3 x^ 2 +2 x-3, f(0)=-3 and 4 g(f(x))=3 x^ 2 -32 x+72 , then f(g(2)) is equal to: JEE Main 2026 Full Functions list Functions JEE Maths PYQsJEE Mathematics PYQs All JEE Main PYQs