Q3 of 164 Page 50

Simplify, using trigonometric tables

tan 45° 27’ + sin 20°

First we consider tan 45° 27’.


We write tan 45° 27’ = tan 45° 24’ + 3’.


The relevant part of the tangent table is given below.



From the table, we have


tan 45° 24’ = 1.0141


Mean difference for 3’ = 0.0018


We know that mean difference is to be added in the case of tangent.


tan 45° 27’ = 1.0141 + 0.0018 = 1.0159


Then, consider sin 20°,


The relevant part of the sine table is given below.



From the table, we have


Sin 20° = 0.3420


tan 45° 27’ + sin 20° = 1.0159 + 0.3240 = 1.3399


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