Answer:
α= 133.6 degrees
(a)Sin(α/2)=0.9191
(b)cos(α/2)=0.3939
(c)Tan(α/2)=2.3332
Step-by-step explanation:
If Tan α= [tex]-\frac{21}{20}[/tex]
90<α<180
We determine first the value of α in the first quadrant
α=[tex]Tan^{-1}\frac{21}{20}[/tex]
=46.4
Since 90<α<180
α=180-46.4=133.6 degrees
(a)Sin(α/2)=Sin(133.6/2)=Sin 66.8 =0.9191
(b)cos(α/2)=cos(133.6/2)=cos 66.8 =0.3939
(c)Tan(α/2)=Tan(133.6/2)=Tan 66.8 =2.3332
