Tangent 3 Theta Formula

The relationship between the basic trigonometric functions taking 3 times the angle in the trigonometric functions of those angles itself, gives The trigonometric triple-angle identities.

You can either expand or simplify the triple angle tan functions like tan 3 A , tan 3 x, tan 3 alpha etc by using triple angle identity.

Tan 3 theta = 3 tan theta – tan 3 theta / 1 – 3 tan2 theta

Where tan is a tangent function and theta is an angle. This is one of the important trigonometry formulas.

Tan 3x Formula Example:

Question: Find the value of A?

Tan 6 A X tan 3 A = 1

Solution: tan 6A =1 / tan 3 A

Tan 6A = cot 3A

Tan 6A = tan(90 – 3A)

6a = 90 – 3a

6A – 3A = 90

3A = 90

A =90/3

A = 30

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Practise This Question

Value of two principal specific heats of a gas in cal (mol K)1 determined by different students are given. Which is most reliable?