Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NDA 2018
Exam
NDA
Year
2018
Subject
Mathematics
Chapter
Functions

NDA 2018 · Mathematics · Functions

Let [x] denote the greatest integer function. What is the number of...

Let [x][\mathrm{x}] denote the greatest integer function. What is the number of solutions of the equation x2−4x+[x]=0x^2-4 x+[x]=0 in the interval [0,2]?[0,2] ?

Options

  1. AZero (No solution)
  2. BOne
  3. CTwo
  4. DThree

Correct answer

B. One

Step-by-step solution

x2−4x+[x]=0x^2-4 x+[x]=0 Given internal, [0,2][0,2] Case 1 : Let 0≤x<1[x]=0∴x2−4x+0=0⇒x(x−4)=0⇒x=0,x=4x=40 \leq \mathrm{x} < 1[\mathrm{x}]=0\therefore x^2-4 x+0=0 \Rightarrow x(x-4)=0 \Rightarrow x=0, x=4x=4 can't be taken in 0≤x<1∴x=00 \leq x < 1\therefore \mathrm{x}=0 Case 2 : Let 1≤x<21 \leq \mathrm{x} < 2[x]=1∴x2−4x+1=0\begin{aligned} & {[\mathrm{x}]=1} \\ & \therefore \mathrm{x}^2-4 \mathrm{x}+1=0 \end{aligned}roots are $\frac{4 \pm \sqrt{16-4}}{2}=\frac{4 \pm \sqrt{12}}{2}=2 \pm \sqrt{3}$ In internal $1 \leq x < 2,2 \pm \sqrt{3}$ are not the roots. Case $3:$ Let $x=2\begin{aligned} & {[\mathrm{x}]=2} \\ & \therefore \mathrm{x}^2-4 \mathrm{x}+2=0 \end{aligned}$$rootsareroots are\frac{4 \pm \sqrt{16-8}}{2}=\frac{4 \pm \sqrt{8}}{2}=2 \pm \sqrt{2}Since,Since,\mathrm{x}=2,rootscan′tbe, roots can't be2 \pm \sqrt{2}\thereforeThereisonlyonesolution,There is only one solution,\mathrm{x}=0$
Practice Functions on Quantrex Academy →

More from Functions

Consider the following statements in respect of the function f(x)=x in the interval… NDA 2026Passage: Consider the curves y=x^2 and y=2|x| . Question: What is the number of points of… NDA 2026If 2f(x)+f(1-x)=x , then what is f(x) equal to ? NDA 2026For the following two (02) items: Consider the function f(x) = 1 - [3] (x-1)^2 . What is… NDA 2025Consider the following for the two (02) items that follow: Let the function y = (1 - x)^… NDA 2025For the following two (02) items: Consider the function f(x) = 10^x - 10^ -x 10^x + 10^… NDA 2025Consider the following for the two (02) items that follow: Let the curve f(x) = |x - 3| .… NDA 2025Consider the following for the two (02) items that follow: Let f = \ (1,1), (2,4), (3,7)… NDA 2025For the following two (02) items: Consider the function f(x) = (x)/(1 - x) (x > 0 , x ≠ 1… NDA 2025Consider the following for the two (02) items that follow: The function f(x) satisfies… NDA 2025Consider the following for the two (02) items that follow: The function f(x) satisfies… NDA 2025Consider the following for the two (02) items that follow: A function f is such that… NDA 2025For the following two (02) items: Consider the function f(x) = (x)/(1 - x) (x > 0 , x ≠ 1… NDA 2025For the following two (02) items: Consider the function f(x) = 10^x - 10^ -x 10^x + 10^… NDA 2025Consider the following for the two (02) items that follow: Let f = \ (1,1), (2,4), (3,7)… NDA 2025Consider the following for the two (02) items that follow: A function f is such that… NDA 2025 Full Functions list Functions JEE Maths PYQsJEE Mathematics PYQs All NDA PYQs