So the answer is :
2{cos 120+ i sin 120)
= 2 cis 120
??
but my solution manual gave me this answer
2 Cis 210
which i myself think is wrong
the table of cos and sin positive value is also used if i m right.and when cos and sin are yielding different results, we go to tangent.ok i...
-1-(under root)3 i
here we find that
r=2(hypotenuse)
a=-1(base)
b=-(under root)3
when i take sin theat= p/h=-(under root)3 / 2
theat from sin is -60
when i take cos theta = b/h =-1 / 2
which gives 120
now one is -60 and other is 120, which is the angel , i have to follow and what...