JEE Advanced 2026 · Continuity and Differentiability
For a real number α, let [α] denote the greatest integer less than or equal to α. For a finite set S, let |S| denote the number of elements in the set S. Consider the functions f:(−3,3)→(−inf, inf) and g:(−3,3)→(−inf, inf) defined by f(x)=[x3]loge(1+sin2(π(x−[x]))) and g(x)=x3sin2(πloge(1+x−[x])). Let A ={x in (-3,3) : f is discontinuous at x} and B={x in (-3,3) : g is discontinuous at x}. Then the value of |A| + 2|B| - |A ∩ B| is ________.
For a real number α, let [α] denote the greatest integer less than or equal to α. For a finite set S, let |S| denote the number of elements in the set S. Consider the functions f: (-3, 3) → (-∞, ∞) and g: (-3, 3) → (-∞, ∞) defined by f(x) = [x³] logₑ(1 + sin²(π(x - [x]))) and g(x) = x³ sin²(π logₑ(1 + x - [x])). Let A = {x ∈ (-3, 3) : f is discontinuous at x} and B = {x ∈ (-3, 3) : g is discontinuous at x}. Then the value of |A| + 2|B| - |A ∩ B| is ________.
f(x)=[x3]loge(1+sin2(π(x−[x])))
g(x)=x3sin2(πloge(1+x−[x]))
domain (−3,3)
A={x:f discontinuous},B={x:g discontinuous}
Find ∣A∣+2∣B∣−∣A∩B∣
1.simplify f
2.count A
3.count B and A∩B
sin2(π(x−[x]))=sin2(πx)
⇒f(x)=[x3]log(1+sin2(πx))
h(x)=log(1+sin2(πx)) is continuous
[x3] jumps where x3∈Z,x3∈(−27,27)
#{x3∈Z}=53(n=−26,−25,…,26)
jump points: x=3n
h=0⇔x∈Z:x=−2,−1,0,1,2(integer cubes)
∣A∣=53−5=48
g(x)=x3sin2(πlog(1+{x}))
x3 continuous⇒break only where {x} jumps (integers)