Answer:
see below
Step-by-step explanation:
cscx=4
sinx=1/4
cosx=-√(1-sin^2x)=-√(1-(1/16))=-√(15/16)=-√15/4
note: cos<0,sin>0 in quadrant II
sin(x/2)= [tex]\sqrt{\frac{1+cos(x)}{2} } =\sqrt\frac{1+\sqrt{\frac{15}{4} } }{2} =\sqrt{\frac{4+\sqrt{15} }{8} }[/tex]
cos(x/2)= [tex]\sqrt{\frac{1-cos(x)}{2} } =\sqrt{\frac{1-\sqrt{\frac{15}{4} } }{2} } =\sqrt{\frac{4-\sqrt{15} }{8} }[/tex]
tan(x/2)= [tex]\frac{sin(x)}{1-cos(x)} =\frac{\frac{1}{4} }{(1-\frac{\sqrt{15} }{4} )} =\frac{\frac{1}{4} }{\frac{4-\sqrt{15} }{4} } =\frac{1}{4-\sqrt{15} }[/tex]
Calculator check:
[tex]sinx=\frac{1}{4}[/tex]
[tex]x\neq 165.52[/tex]˚ in quadrant II
[tex]\frac{x}{2} \neq 82.76[/tex] ˚
sin(x/2)≈sin(82.76)≈0.9920..
exact value=√(4+√15)/8≈0.9920..
..
cos(x/2)≈cos(82.76)≈0.1260..
exact value=√(4-√15)/8≈0.1260..
..
tan(x/2)=tan(82.76)≈7.872..
exact value=1/(4-√15)≈7.872..
