Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Let a function f : R $\to$ R be defined as $$f(x) = \left\{ {\matrix{ {\sin x - {e^x}} & {if} & {x \le 0} \cr {a + [ - x]} & {if} & {0 < x < 1} \cr {2x - b} & {if} & {x \ge 1} \cr } } \right.$$

where [ x ] is the greatest integer less than or equal to x. If f is continuous on R, then (a + b) is equal to:

  1. A 4
  2. B 3 Correct answer
  3. C 2
  4. D 5

Solution

Continuous x = 0<br><br>f(0<sup>+</sup>) = f(0<sup>$-$</sup>) $\Rightarrow$ a $-$ 1 = 0 $-$ e<sup>0</sup><br><br>$\Rightarrow$ a = 0<br><br>Continuous at x = 1<br><br>f(1<sup>+</sup>) = f(1<sup>$-$</sup>)<br><br>$\Rightarrow$ 2(1) $-$ b = a + ($-$1)<br><br>$\Rightarrow$ b = 2 $-$ a + 1 $\Rightarrow$ b = 3<br><br>$\therefore$ a + b = 3

About this question

Subject: Mathematics · Chapter: Limits, Continuity and Differentiability · Topic: Limits and Standard Results

This question is part of PrepWiser's free JEE Main question bank. 162 more solved questions on Limits, Continuity and Differentiability are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →