If tan θ = 1/2 and tan ϕ = 1/3, Find the Value of θ + ϕ

If tan θ = 1/2 and tan ϕ = 1/3, Find the Value of θ + ϕ

Question:
If \[ \tan\theta=\frac{1}{2} \] and \[ \tan\phi=\frac{1}{3} \] then the value of \[ \theta+\phi \] is
(a) \(\frac{\pi}{6}\)
(b) \(\pi\)
(c) \(0\)
(d) \(\frac{\pi}{4}\)

Solution

Using the tangent addition formula:

\[ \tan(\theta+\phi) = \frac{ \tan\theta+\tan\phi } { 1-\tan\theta\tan\phi } \]

Substituting the given values,

\[ \tan(\theta+\phi) = \frac{ \frac{1}{2}+\frac{1}{3} } { 1-\frac{1}{2}\cdot\frac{1}{3} } \]

\[ = \frac{ \frac{5}{6} } { 1-\frac{1}{6} } \]

\[ = \frac{ \frac{5}{6} } { \frac{5}{6} } \]

\[ =1 \]

Therefore,

\[ \tan(\theta+\phi)=1 \]

Hence,

\[ \theta+\phi=\frac{\pi}{4} \]

Final Answer

\[ \boxed{ \theta+\phi=\frac{\pi}{4} } \]

Correct Option: (d)

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