Question

Find the values of the following trigonometric ratio.

tan(-855°)

Answer 1

tan(-855°) = -tan 855° (∵ tan(-θ) = – tan θ)

[∵ Multiplies of 360° are dropped out. For 180° – 45°. No change in T-ratio. 180° – 45° lies in 2nd quadrant ‘tan’ is negative]

= -tan(2 × 360° + 135°)

= -tan 135°

= -tan(180° – 45°)

= -(-tan 45°)

= -(-1)

= 1