Mathematics · Functions

JEE Main 2024 — 1 February, Shift 2 — Question 13

If the domain of the function f(x)=x2−25(4−x2)f(x)=\frac{\sqrt{x^{2}-25}}{\left(4-x^{2}\right)} +log⁡10(x2+2x−15)+\log _{10}\left(x^{2}+2 x-15\right) is (−∞,α)U[β,∞)(-\infty, \alpha) U[\beta, \infty), then α2+β3\alpha^{2}+\beta^{3} is equal to :

  1. Option A:

    140

  2. Option B:

    175

  3. Option C:

    150

    Correct
  4. Option D:

    125

Answer: C

Step-by-step solution

f(x)=x2−254−x2+log⁡10(x2+2x−15)f(\mathrm{x})=\frac{\sqrt{\mathrm{x}^{2}-25}}{4-\mathrm{x}^{2}}+\log _{10}\left(\mathrm{x}^{2}+2 \mathrm{x}-15\right)

Domain : x2−25≥0⇒x∈(−∞,−5]∪[5,∞)\mathrm{x}^{2}-25 \geq 0 \Rightarrow \mathrm{x} \in(-\infty,-5] \cup[5, \infty)

4−x2≠0⇒x≠{−2,2}4-x^{2} \neq 0 \Rightarrow x \neq\{-2,2\}

x2+2x−15>0⇒(x+5)(x−3)>0\mathrm{x}^{2}+2 \mathrm{x}-15>0 \Rightarrow(\mathrm{x}+5)(\mathrm{x}-3)>0

⇒x∈(−∞,−5)∪(3,∞)\Rightarrow \mathrm{x} \in(-\infty,-5) \cup(3, \infty)

∴x∈(−∞,−5)∪[5,∞)\therefore \mathrm{x} \in(-\infty,-5) \cup[5, \infty)

α=−5;β=5\alpha=-5 ; \beta=5 ∴α2+β3=150\therefore \alpha^{2}+\beta^{3}=150

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Mathematics
Chapter
Functions
Topic
Domain & range of functions
If the domain of the function f(x)=frac sqrt x 2 -25 (4-x 2 ) +log 10… | JEE Main 2024 PYQ with Solution · DhiX AI