problema 2
\(\vec{A}=\sqrt{ax^2+ay^2}\)  \(=\sqrt{\left(-25\right)^2+\left(40\right)^2}\)  =\(\sqrt{625+1600}\)
\(\sqrt{2225}\)\(=47.16\)
\(\tan\theta=\frac{Ay}{Ax}=\theta=\tan^{-1}\left(\frac{40}{-25}\right)=-57.99\)