Question Number 186027 by Michaelfaraday last updated on 31/Jan/23
Answered by qaz last updated on 31/Jan/23
$$\frac{{d}\mid{y}\mid}{{dx}}=\begin{vmatrix}{\mathrm{sin}\:{x}}&{\mathrm{sin}\:{x}}\\{−\mathrm{sin}\:{x}}&{−\mathrm{sin}\:{x}}\end{vmatrix}+\begin{vmatrix}{\mathrm{cos}\:{x}}&{\mathrm{cos}\:{x}}\\{\mathrm{cos}\:{x}}&{\mathrm{cos}\:{x}}\end{vmatrix}=\mathrm{0} \\ $$