Use the halfangle identities to find the desired function va

Use the half-angle identities to find the desired function value. Assume that x >/= to 0.

If cos x = -1/4 and csc x < 0, find cot(x/2)

Solution

cos x = -1/4 and csc x < 0

=>x is in third quadrant

<=x<=3/2

=>/2<=x/2<=3/4

=>x/2 is in second quadrant

=>sin(x/2)>0, cos(x/2)<0

sin(x/2)=((1/2)[1-cosx]),cos(x/2)=-((1/2)[1+cosx])

=>sin(x/2)=(1/2)[1-(-1/4)],cos(x/2)=-((1/2)[1+(-1/4)])

=>sin(x/2)=(5/8),cos(x/2)=-(3/8)

cot(x/2)=cos(x/2)/sin(x/2)

cot(x/2)=-(3/8)/(5/8)

cot(x/2)=-(3/5)

Use the half-angle identities to find the desired function value. Assume that x >/= to 0. If cos x = -1/4 and csc x < 0, find cot(x/2)Solutioncos x = -1/4

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