If tan A = frac{1}{2}, then tan 3A =

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3.Trigonometrical Ratios, Functions and Identities

easy

If $\tan A = \frac{1}{2},$ then $\tan 3A = $

A

$\frac{9}{2}$

B

$\frac{{11}}{2}$

C

$\frac{7}{2}$

D

$ - \frac{1}{2}$

Solution

(b) We have $\tan A = \frac{1}{2}$

$ \Rightarrow \tan 3A = \frac{{3\tan A – {{\tan }^3}A}}{{1 – {{3+an }^2}A}} $

$= \frac{{3.\frac{1}{2} – \frac{1}{8}}}{{1 – 3.\frac{1}{4}}} $

$= \frac{{12 – 1}}{2} = \frac{{11}}{2}$.

Standard 11

Mathematics

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