Question Number 18908 by Nayon last updated on 01/Aug/17
$${Why}\:{Does} \\ $$$$\mid\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\mid={ABSin}\theta\:? \\ $$
Commented by mrW1 last updated on 02/Aug/17
$$\mathrm{You}\:\mathrm{can}\:\mathrm{not}\:\mathrm{ask}\:\mathrm{why}\:\mathrm{to}\:\mathrm{a}\:\mathrm{definition}. \\ $$$$\mathrm{It}\:\mathrm{is}\:\mathrm{just}\:\mathrm{as}\:\mathrm{it}\:\mathrm{is}\:\mathrm{defined}.\:\mathrm{You}\:\mathrm{can} \\ $$$$\mathrm{consult}\:\mathrm{a}\:\mathrm{book}\:\mathrm{about}\:\mathrm{vectors}\:\mathrm{for}\:\mathrm{more} \\ $$$$\mathrm{details}. \\ $$
Commented by mrW1 last updated on 02/Aug/17
Commented by Nayon last updated on 03/Aug/17
$${Can}'{t}\:{we}\:{proof}\:{them}\:{mr}.{w}\mathrm{1}?? \\ $$
Commented by ajfour last updated on 03/Aug/17
$$\mathrm{see}\:\mathrm{into}\:\mathrm{the}\:\mathrm{property}\:\mathrm{of}\:\mathrm{what}\:\mathrm{they} \\ $$$$\mathrm{do}.\:\mathrm{dot}\:\mathrm{product}\:\mathrm{helps}\:\mathrm{take}\:\mathrm{component}, \\ $$$$\mathrm{while}\:\mathrm{cross}\:\mathrm{product}\:\mathrm{helps}\:\mathrm{rotation}. \\ $$
Commented by ajfour last updated on 03/Aug/17
