Verify this trig identity csc x cot x2 1cosx 1 cos xSolu
Verify this trig identity. (csc x - cot x)^2 = (1-cosx / 1 + cos x)
Solution
given that
(csc x - cot x)^2 = (1- cosx / 1+cosx )
L.H.S = (csc x - cost x)^2
but csc x = 1/sin x and cot x = cos x /sin x
L.H.S = (1/sin x - cosx /sinx)^2
= (1- cos x / sin x)^2
= (1- cos x)^2 / (sinx)^2
= (1- cos x)^2 / 1- cos^2 x [ by using sin^2 x + cos^2 x=1 ]
= (1- cos x)^2 / (1+ cos x) (1-cosx)
=[ (1-cosx) (1-cosx) ] / [ (1+ cos x) (1-cosx)]
= 1-cos x / 1+ cosx
L.H.S = R.H.S
hence proved
