forgot how to solve these

[red and white kop!]

find, to 1 decimal place, all values of z in the interval -180 < z < 180 satisfying
- cos(z)(1+sin(z))= 0
- (1-tan(z))sin()z= 0

the problem here is i don't even know how to sort these out algebraically so i can then find the trig values. for example on the first question:
taking z(1+sin(z))= A
cosA= 0 for -90 and 90
so i have z(1+sin(z))=-90, 90
and i blank out on how to solve!

 

[tkhunny]

With already factored equations, you should proceed as in elementary algebra, using this property,

If a*b = 0, then either a = 0 or b = 0.

This, if cos(z) * (1+sin(z)) = 0, then either cos(z) = 0 or 1+sin(z) = 0. Solve those two much simpler equations.