Cosec x =1/sin x
Cot x = cos x/sin x
Cosec x ? cot x = (1-cos x)/sin x
=>1-cos x = p sin x
P+1/p = (1-cos x)/ sin x + sin x /1-cos x
_____= [1+cos2 x ? 2 cos x + sin2 x] / (sin x) (1-cos x) ------------by taking LCM
_____= [1+1-2 cos x] / (sin x) (1-cos x) ----------since sin2 x+ cos2 x =1
_____= [2-2 cos x] / (sin x) (1-cos x) -------by taking ?2? common
_____= 2{1-cos x}/ (sin x) (1-cos x) -------- (1-cos x) in numerator & denominator
_____= 2 / sin x
_____= 2 cosec x
Therefore, cosec x = ½ (p + 1/p)