Let $\eta_2$ be the generator of $\pi_3(S^2)$, i.e. the Hopf map. $i_1:S^2 \hookrightarrow S^2\vee S^2$ and $i_2:S^2 \hookrightarrow S^2\vee S^2$ are the inclution maps respectively. then $[i_1\circ \eta_2,i_2]=?$ where $[,]$ is the whitehead product.
