Solution
Express the given trigonometric functions in terms of the same function of a positive acute angle.
1.
[tex]sin150\degree=sin(180-150)[/tex]
sin150 = is in the second quadrant and its positive
[tex]\begin{gathered} sin(180-150)=sin30 \\ =sin30 \\ =\frac{1}{2} \\ =0.5 \end{gathered}[/tex]
2.
[tex]cos240=cos(240-180_)[/tex]
Cos240 = is in the third quadrant and its negative
[tex]\begin{gathered} cos(240-180) \\ =-cos60 \\ =-\frac{1}{2} \\ =-0.5 \end{gathered}[/tex]
