secxtanx cotx cscxcos2 x is this a trig identitySolutiongi
secx(tanx + cotx = cscx/cos^2 x is this a trig identity
Solution
given
secx(tanx +cotx) = cscx/cos^2x
to prove take left hand side
LHS = secx(tanx +cotx)
now secx = 1/cosx , tanx = sinx/cosx and cotx = cosx/sinx , plug all these values
L.H.S= 1/cosx ( sinx /cosx + cosx /sinx)
= 1/cosx[ (sin^2 x +cos^2 x) /cosxsinx ]
but sin^2 x +cos^2 x=1
so
L.H.S= 1/cosx [ 1/ cosxsinx ]
= 1/(cos^2 x sinx)
but 1/sinx = cscx
L.H.S = cscx/cos^2 x
L.H.S=R.H.S
so hence proved
