Question Number 164524 by daus last updated on 18/Jan/22
Answered by mindispower last updated on 18/Jan/22
$${polar}\:{coordinat}\:\left({r},{a}\right)\Rightarrow\left({r},{a}+\frac{\pi}{\mathrm{4}}\right) \\ $$
Commented by mindispower last updated on 18/Jan/22
$${cos}\left({a}+\frac{\pi}{\mathrm{4}}\right)=\frac{\mathrm{1}}{\:\sqrt{\mathrm{2}}}\left({cos}\left({a}\right)−{sin}\left({a}\right)\right) \\ $$