v}^{4} { - 6v}^{3} " alt=" { - 2v}^{4} { - 6v}^{3} " align="absmiddle" class="latex-formula"> Please factor out the common factor out of each expression
You can use trigonometry specially the cos rule in this case. I can’t send the other pictures. But using the cos rule you can check whether the angle is 90
