sec (70° - θ) = cosec (20° + θ)

Given equation : sec (70° - θ) = cosec (20° + θ)

Solving L.H.S.

⇒ sec (70° - θ)

⇒ sec [90° - (20° + θ)]

By formula,

sec (90° - θ) = cosec θ

⇒ cosec (20° + θ)

Since, L.H.S. = R.H.S.

Hence, proved that sec (70° - θ) = cosec (20° + θ).