ExamBro
ExamBro
JEE Advanced · Mathematics · 25. AOD

Let \(\mathbb{R}\) denote the set of all real numbers. For a real number \(x\), let \([x]\) denote the greatest integer less than or equal to \(x\). Let \(n\) denote a natural number.
Match each entry in List-I to the correct entry in List-II and choose the correct option.
LIST - I LIST - II
(P) The minimum value of \(n\) for which the function \(f(x)=\left[\frac{10 x^3-45 x^2+60 x+35}{n}\right]\) is continuous on the interval \([1,2]\),is (1) 8
(Q) The minimum value of \(n\) for which \(g(x)=\left(2 n^2-13 n-15\right)\left(x^3+3 x\right),x \in \mathbb{R}\),is an increasing function on \(\mathbb{R}\),is (2) 9
(R) The smallest natural number \(n\) which is greater than 5,such that \(x=3\) is a point of local minima of \(h(x)=\left(x^2-9\right)^{\mathrm{n}}\left(x^2+2 x+3\right)\),is (3) 5
(S) Number of \(x_0 \in \mathbb{R}\) such that \(l(x)=\sum_{k=0}^4\left(\sin |x-k|+\cos \left|x-k+\frac{1}{2}\right|\right),x \in \mathbb{R}\),is NOT differentiable at \(x_0\),is (4) 6
(5) 10

  1. A \((\mathrm{P}) \rightarrow(1),(\mathrm{Q}) \rightarrow(3),(\mathrm{R}) \rightarrow(2),(\mathrm{S}) \rightarrow(5)\)
  2. B \((\mathrm{P}) \rightarrow(2),(\mathrm{Q}) \rightarrow(1),(\mathrm{R}) \rightarrow(4),(\mathrm{S}) \rightarrow(3)\)
  3. C \((\mathrm{P}) \rightarrow(5),(\mathrm{Q}) \rightarrow(1),(\mathrm{R}) \rightarrow(4),(\mathrm{S}) \rightarrow(3)\)
  4. D \((\mathrm{P}) \rightarrow(2),(\mathrm{Q}) \rightarrow(3),(\mathrm{R}) \rightarrow(1),(\mathrm{S}) \rightarrow(5)\)
Verified Solution

Answer & Solution

Correct Answer

(B) \((\mathrm{P}) \rightarrow(2),(\mathrm{Q}) \rightarrow(1),(\mathrm{R}) \rightarrow(4),(\mathrm{S}) \rightarrow(3)\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned}
& P(x)=10 x^3-45 x^2+60 x+35 \\
& P^{\prime}(x)=30(x-1)(x-2)
\end{aligned}\)
\(\mathrm{P}(\mathrm{x})\) decreases in \([1,2]\)
\(\Rightarrow\) Range of \(\mathrm{P}(\mathrm{x})=[55,60]\)
\(f(\mathrm{x})=\left[\frac{\mathrm{P}(\mathrm{x})}{\mathrm{n}}\right] \min\) value of \(\mathrm{n}=9\)
(Q) For \(g(x)\) to be increasing
\(2 n^2-13 n-15 \geq 0\)

(R) \(\begin{aligned} & h(x)=\left(x^2-9\right)^n\left(x^2+2 x+3\right) \\ & h^{\prime}(x)=\left(x^2-9\right)^n(2 x+2)+\left(x^2+2 x+3\right) n\left(x^2-9\right)^{n-1} \cdot 2 x \\ & =\left(x^2-9\right)^{n-1}\left[2\left(x^2-9\right)(x+1)+2 n x\left(x^2+2 x+3\right)\right] \\ & =(x+3)^{n-1}(x-3)^{n-1} \cdot q(x)\end{aligned}\)
Derivative must change sign at \(x=3\)
\(\begin{aligned}
& \because \mathrm{n}-1=\text { odd } \\
& \mathrm{n}=\text { even } \\
& \mathrm{n}=6
\end{aligned}\)
(S) \(\cos \left|\mathrm{x}-\mathrm{k}+\frac{1}{2}\right|\) is differentiable everywhere
\(\Rightarrow \sin |\mathrm{x}-\mathrm{k}|\) is NOT diff. at \(\mathrm{k}=0,1,2,3,4\)
Same subject
Explore more questions on app