Question

The solution to the following differential equation y′′+9y=0, y(0)=1,y′(0)=3 is

Answer 1

Given y''  + 9y = 0

y'' = - 9y

On integrating on the both sides,

y' = - 9y²/2 + c

On substituting the given values and further solving we can get the values of c.

Put the value of c in the above bolded eqn. to get the GENERAL SOLUTION.

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