How 1 + tan²θ = sec²θ?

Derivation of tan²θ + 1 = sec²θ

As we know that,

              Sin²θ + Cos²θ = 1 

........👉👉(Derivation of Sin²θ + Cos²θ = 1)

Divide by Cos²θ both sides ,

   we get,

Sin²θ/Cos²θ + Cos²θ/Cos²θ = 1/Cos²θ

Hence,   tan²θ + 1 = sec²θ