Mathematics · Limits, Continuity and Differentiability

JEE Main 2026 — 23 January, Evening Shift — Question 1

If f(x)={a∣x∣+x2−2(sin⁡∣x∣)(cos⁡∣x∣)x,x≠0b,x=0f(x)=\left\{\begin{array}{cl}\frac{a|x|+x^{2}-2(\sin |x|)(\cos |x|)}{x} & , x \neq 0\\ b & , x=0\end{array}\right. is continuous at x=0\mathrm{x}=0, then a+b\mathrm{a}+\mathrm{b} is equal to :

  1. Option A:

    1

  2. Option B:

    2

    Correct
  3. Option C:

    0

  4. Option D:

    4

Answer: B

Step-by-step solution

f(x)={a∣x∣+x2−2sin⁡∣x∣cos⁡∣x∣x;x≠0bx=0f(x)=\left\{\begin{array}{cc}\frac{a|x|+x^{2}-2 \sin |x| \cos |x|}{x} & ; x \neq 0 \\b & x=0\end{array}\right.

for continuity lim⁡x→0−f(x)=lim⁡x→0+f(x)=f(0)\lim _{x \rightarrow 0^{-}} f(x)=\lim _{x \rightarrow 0^{+}} f(x)=f(0)

lim⁡x→0−ah+h2−2(sinh⁡)cosh⁡−h\lim _{\mathrm{x} \rightarrow 0^{-}} \frac{\mathrm{ah}+\mathrm{h}^{2}-2(\sinh ) \cosh }{-\mathrm{h}}

=lim⁡x→0+ah+h2−2(sinh⁡)cosh⁡h=\lim _{\mathrm{x} \rightarrow 0^{+}} \frac{\mathrm{ah}+\mathrm{h}^{2}-2(\sinh ) \cosh }{\mathrm{h}} or −a+2=a−2=b-\mathrm{a}+2=\mathrm{a}-2=\mathrm{b}

2a=42 \mathrm{a}=4

a=2, b=0\mathrm{a}=2, \mathrm{~b}=0

∴a+b=2\therefore \mathrm{a}+\mathrm{b}=2

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Limits, Continuity and Differentiability
Topic
Continuity
If f(x)= \ begin array cl frac a x +x 2 -2(sin x )(cos x ) x & , x… | JEE Main 2026 PYQ with Solution · DhiX AI