Re: math problem :( show that something = something else

> z=a-x -> dz/dy = -dx/dy -> d^2z/dy^2 = -d^2x/dy^2
>
> Thus:
>
> EI(-d^2z/dy^2) = Mgz
>
> d^2z/dy^2 + (Mg/EI)z = 0
>
>
> Hope someone can help me out
>
> Thanks in advance

Looks like a pretty straight forward "linear homogeneous equation with constant coefficients" to me. Should be just about the first thing you learn in differential equations.
The associated "characteristic equation" is
r^2+ (Mg/EI)= 0 which has imaginary solutions r= +/- sqrt(Mg/EI) i and so the differential equation has general solution z(y)= C_1 cos(sqrt(Mg/EI)y)+ C_2 sin(sqrt(Mg/EI)y)

If you don't understand that, then notice that the problem only asks you to show that a given function IS a solution. What happens if you take the function you are given, differentiate twice, and put it into the equation?
.

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