Bobosharif S. answered 12/19/17
Tutor
4.4
(32)
Mathematics/Statistics Tutor
CosecA+cotA=k
coces(A)=1/sin(A), So
1/sin(A)+cos(A)/sin(A)=k
(1+cos(A))/sin(A))=k
2cos2(A/2)/2sin(A/2)cos(A/2)=k
cos(A/2)/sin(A/2)=k
cot(A/2)=k
tan(A/2)=1/k
(1-cos(A))/(1+cos(A))=1/k^2
cos(A)=(k^2+1)/(k^2-1)