prove that sec + tan -1 / tan -sec+1 = cos /1-sin

note : here 2 means square

LHS sec+tan - (sec2 - tan 2)/tan -sec + 1

take common sec + tan (1-sec + tan)/tan-sec+1

sec + tan

1/cos + sin/cos

1+sin/cos

multiply numerator and denominator by 1-sin

we get

1-sin2/cos-cos sin

take cos common from denominator and 1-sin2 is cos2

cos2/cos(1-sin)

cos/1-sin = RHS