To prove sin1 / [Cosn ° * cos (n + 1) °] = Tan (n + 1) ° - Tan °

To prove sin1 / [Cosn ° * cos (n + 1) °] = Tan (n + 1) ° - Tan °

The key here is the communication angle: change the left 1 ° to (n + 1) ° - n ° to sin1 / [Cosn ° * cos (n + 1) °] = sin [(n + 1) ° - n °] / [Cosn ° * cos (n + 1) °] = [sin (n + 1) ° - cos (n + 1) ° Sinn °] / [Cosn ° * cos (n + 1) °] = Tan (n + 1)