Verified Solution • 2025–26 Session moderate

QJEEM21Mac764: JEE Main 2021 Mathematics - Class 12 JEEM21Mac764 Solution: Let a function f : R R be defined as f ( x ) = { sin ⁡ x − e x…

Let a function f : R →\to R be defined as f(x)={sin⁡x−exifx≤0a+[−x]if0<x<12x−bifx≥1

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

Multiple Choice Options

  • A 4
  • B 3
  • C 2
  • D 5

Step-by-Step Verified Solution

Continuous x = 0

f(0+) = f(0 −- ) ⇒\Rightarrow a −- 1 = 0 −- e0

⇒\Rightarrow a = 0

Continuous at x = 1

f(1+) = f(1 −- )

⇒\Rightarrow 2(1) −- b = a + ( −- 1)

⇒\Rightarrow b = 2 −- a + 1 ⇒\Rightarrow b = 3

∴\therefore a + b = 3

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