cuesulon Two vectors vec$(P)$ and vec$(Q)$ have equal magnitudes. If the magnitude of vec$(P)+$vec$(Q)$ is $n$ times the magnitude of vec$(P)-$vec$(Q)$ then angle between vec$(P)$ and vec$(Q)$ is: $[$IEE Main$-2021]si{n}^{-1}(\frac{n-1}{n+1})co{s}^{-1}(\frac{n-1}{n+1})si{n}^{-1}(\frac{n^2-1}{n^2+1})co{s}^{-1}(\frac{n^2-1}{n^2+1})$ Ans: $(4)$