(Cos A/Sin A )+(1/Sin A)= 5 .
Show that Cos A=12/13.
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(CosA/SinA)+(1/SinA) = 5
(cosA+1)/sinA = 5
{2cos^2(A/2)} / 2sin(A/2)*cos(A/2) = 5
tan(A/2) = 5
so, sin(A/2) = 5/root26
sin^2(A/2) = 25/26
2sin^2(A/2) = 50/26
we know that,
cosA = 1-2sin^2(A/2)
cosA = 1-50/26
cosA = 24/26=12/13
(cosA+1)/sinA = 5
{2cos^2(A/2)} / 2sin(A/2)*cos(A/2) = 5
tan(A/2) = 5
so, sin(A/2) = 5/root26
sin^2(A/2) = 25/26
2sin^2(A/2) = 50/26
we know that,
cosA = 1-2sin^2(A/2)
cosA = 1-50/26
cosA = 24/26=12/13
dheeerajbolisetti:
it is easy there is another formula cosA=1-tan^2A/2 /1+tan^2a/2
yes ,i forgot
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0
i got the answer :D :D
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