We have the following differential equation

$\cup {}^{\u2033}=1+{\left({u}^{\prime}\right)}^{2}$

i found that the general solution of this equation is

$u=d\text{cosh}((x-\frac{b}{d})$

where b and d are constats

Please how we found this general solution?

i found that the general solution of this equation is

where b and d are constats

Please how we found this general solution?