Simplify, using trigonometric tables

tan 63°12’ – cos 12°42’

First we consider tan 63° 12’,

The relevant part of the tangent table is given below.

From the table, we have

tan 63° 12’ = 1.9797

Then consider cos 12° 42’,

The relevant part of the cosine table is given below.

From the table, we have

cos 12° 42’ = 0.9755

∴ tan 63° 12’ – cos 12° 42’ = 1.9797 – 0.9755 = 1.0042