Arithmetics of '$\wedge$' and '$d$' operators

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I don't find arithemtic rules of the operators $\wedge$ and $d$. For example, why does this equality hold? $$ \\ (u^2\cos^2v+u^2\sin^2v)[\cos vdu-u\sin vdv]\wedge [\sin vdu+u\cos vdv] \ \\ +u\cos v[\cos v du-u\sin vdv]\wedge du \ \\ +u \sin v[\sin v du+u\cos v dv]\wedge dv\ \\ = u(u^2+1) du\wedge dv\ $$