MCQ
Let $[x]$ be the greatest integer less than or equal to $x$ for a real number $x$ Then the equation $\left[x^2\right]=x+1$ has
  • A
    two solutions
  • B
    one solution
  • No solution
  • D
    More than two solutions

Answer

Correct option: C.
No solution
c
(c)

We have, $\left[x^2\right]=x+1$

Clearly, Eq.$(i)$ $\Rightarrow x$ is an integer $\quad \ldots (ii)$

$x^2-\left\{x^2\right\} =x+1$

$\Rightarrow \quad x^2-x-1 =\left\{x^2\right\}$

$Eq.(iii) \Rightarrow x^2-x-1 < 1$

$\Rightarrow \quad-1 < x < 2 \quad \ldots$ (iv)

From Eqs.$(ii)$ and $(iv)$ $\Rightarrow$ possible values of $x$ are $0$ and $1 .$

But $0$ and $1$ do not satisfy Eq.$(i)$.

$\therefore$ Equation $\left[x^2\right]=x+1$ has no soltuion.

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