Q20 of 45 Page 1

If y = 3 cos(log x) + 4 sin(log x), show that

x^2 d^2y/dx^2 + x dy/dx + y = 0

Given y = 3 cos (log x) + 4 sin (log x) … (1)


Differentiating with respect to x, we get





Again differentiating with respect to x, we get




= -y [from (1)]



Hence proved.


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