the forumula i gave is a general formula. u can try it on a calculator if u forget formals (that's what i do
)
for example :
sin(30)=0.5 | k=0
sin(30+360)=0.5 | k=1
sin(30+ 720)=0.5 | k=2
and so on.. this applies in the above formula, note that the above formula is in radians
if u want to use degrees, which is ur domain 0<x<360 ( eza radians bekoun 0<x<2*
pi )
pi(radians)=180 degrees
so the formula for degrees is sin(x)=sin(x+360*k) k is an integer
in ur given problem :
sin(45)=sin(3x + 18)
u put : 45=3x+18
which only gives u the value of k=0 from my formula but in fact there are more solutions
now apply my formula
3x+18=45+360*k
x= (360*k + 27)/3
x=120*k + 9
now u substitute all values of k such that u obey ur domain.
k=0 ~> x=9
k=1 ~> x=129
k=2 ~> x=249
k=3 ~> x=369
which is not in the domain, and so for all values of k=>3
so the solution final solution is
x=9 x=129 x=249
i can't make it any more clear :P