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Question: If \(\tan \alpha , \tan \beta , \tan \gamma\) are the roots of the equation <img src="https://cdn.p...

If tanα,tanβ,tanγ\tan \alpha , \tan \beta , \tan \gamma are the roots of the equation

then the value of

(1 + tanα) (1 + tan2β) (1 + tan2γ) is equal to

A
B
C
D

None of these

Answer
Explanation

Solution

From the given equation we have tanα=p\sum \tan \alpha = p

tanαtanβ=0\sum \tan \alpha \tan \beta = 0 and tanαtanβtanγ=r\tan \alpha \tan \beta \tan \gamma = \mathrm { r }

so that (1+tan2α)(1+tan2β)(1+tan2γ)\left( 1 + \tan ^ { 2 } \alpha \right) \left( 1 + \tan ^ { 2 } \beta \right) \left( 1 + \tan ^ { 2 } \gamma \right)

=1+tan2α+tan2αtan2β+tan2αtan2βtan2γ1 + \sum \tan ^ { 2 } \alpha + \sum \tan ^ { 2 } \alpha \tan ^ { 2 } \beta + \tan ^ { 2 } \alpha \tan ^ { 2 } \beta \tan ^ { 2 } \gamma

=1+(tanα)22tanαtanβ+(tanαtanβ)2\left( \sum \tan \alpha \right) ^ { 2 } - 2 \sum \tan \alpha \tan \beta + \left( \sum \tan \alpha \tan \beta \right) ^ { 2 } 2tanαtanβtanβtanα+tan2αtan2βtan2γ- 2 \tan \alpha \tan \beta \tan \beta \sum \tan \alpha + \tan ^ { 2 } \alpha \tan ^ { 2 } \beta \tan ^ { 2 } \gamma = 1 + p22pr+r2\mathrm { p } ^ { 2 } - 2 \mathrm { pr } + \mathrm { r } ^ { 2 }

=