Question

how to find value of tan 40°.

answer if u know and don't write see on u-tube or Google.

Answer 1

As we know, tan x = sin x/cos x

one way to find is using the values of sin 40 and cos 40.

or you can use the trignometric results:in the pic

similarly, using second formula:

tan (30 + 10) = tan 30 + tan 10 / (1-tan 30 tan 10)

tan 40 = 0.57735 + 0.176326 / ( 1-0.1018) ——→ values are approximated

= 0.753676/0.8982

tan 40 = 0.839095 —-> value of tan 40 by formula.

value by calculator = 0.8390996

They are very nearly equal