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Show that the function y = A cos x + B sin x is a solution of the differential equation \(\frac{d^2y}{dx^2}+y = 0.\) |
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Answer» The differential equation is \(\frac{d^2y}{dx^2}+y = 0\) and the function that is to be proven as solution is y = A cos x + B sin x, now we need to find the value of \(\frac{d^2y}{dx^2}.\) \(\frac{dy}{dx}\) = –A sin x + B cos x \(\frac{d^2y}{dx^2}\) = = –A cos x – B sin x Putting the values in equation, we get, –A cos x – B sin x + A cos x + B sin x = 0, 0 = 0 As, L.H.S = R.H.S. the equation is satisfied, hence this function is the solution of the differential equation. |
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