Find the value of the following.

cos 12^o 35’

We write cos 12° 35’ = cos 12° 30’ + 5’.

The relevant part of the cosine table is given below.

From the table, we have

cos 12° 30’ = 0.9763

Mean difference for 5’ = 0.0003

We know that mean difference is to be subtracted in the case of cosine.

∴ cos 12° 35’ = 0.9763 - 0.0003 = 0.9760