Answer:
1. B.
2. B.
Step-by-step explanation:
Trigonometry
1) Coterminal angles can be found by adding or subtracting 360┬░ (or 2\pi radians) to a given angle. If we have 120┬░, adding 360┬░ gives 480┬░, adding again 360┬░ gives 840┬░. There is no way to get -180┬░, so this option is not a coterminal angle to 120┬░
2)
A. [tex]Cos (-90^o)=0[/tex], and not undefined
B. [tex]Sin (-90^o)=-1[/tex]. This is correct
C. ┬а[tex]Tan (-90^o)[/tex] is undefined, not zero
Thus the only correct option is B.
