Hi All,

Given $\displaystyle u (x) = Ae^x $ and $\displaystyle u"(x)=k^2 u (x)$

then u"(x) is calculated as $\displaystyle u"(x) = A^2 u (x)$

How was this derived?

I calculate both u'(x) and u"(x) to be equal to Ae^x. I dont know how the A^2 appears in front of u(x)!!!.....

Thanks