cos(a-180)=?sin(a-360)=?

cos(a-180)=?sin(a-360)=?

cos(a-180)=-cosa,sin(a-360)=sina.

cos(540-α)sin(α-360)/sin(-α+180)cos(180+α)

=cosαsinα/-sinαcosα
=-1

How to solve (n-2) 180 + 360 / N = 1830
Must have the solution step, the content is clear

Broken bracket 180n-360 + 360 / N = 1830
General division (multiply n) 180n ^ 2-2190n + 360 = 0
Factorization of cross multiplication after reduction 18-3
1 -12
Then (18n-3) (n-12) = 0
So n = 1 / 6 or 12

The minimum value of a number is ()

If you add 3 to this number, it will be exactly divided by 7, 9 and 11;
7. The least common multiple of 9 and 11 is: 7 * 9 * 11 = 673
So the minimum value of this number is: 673-3 = 670