Medium INTEGER +4 / -1 PYQ · JEE Mains 2021

Let a curve y = f(x) pass through the point (2, (loge2)2) and have slope ${{2y} \over {x{{\log }_e}x}}$ for all positive real value of x. Then the value of f(e) is equal to ______________.

Answer (integer) 1

Solution

$y' = {{2y} \over {x\ln x}}$<br><br>$\Rightarrow {{dy} \over y} = {{2dx} \over {x\ln x}}$<br><br>$\Rightarrow \ln |y| = 2\ln |\ln x| + C$<br><br>put x = 2, y = (ln2)<sup>2</sup><br><br>$\Rightarrow$ c = 0<br><br>$\Rightarrow$ y = (lnx)<sup>2</sup><br><br>$\Rightarrow$ f(e) = 1

About this question

Subject: Mathematics · Chapter: Differential Equations · Topic: Order and Degree

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