If tan(π4+θ)+tan(π4−θ)=3, then the value of tan3(π4+θ)+tan3(π4−θ) is
Open in App
Solution
tan(π4+θ)+tan(π4−θ)=3
Cubing both the sides [tan(π4+θ)+tan(π4−θ)]3=27⇒tan3(π4+θ)+tan3(π4−θ)+3tan(π4+θ)⋅tan(π4−θ)[tan(π4+θ)+tan(π4−θ)]=27⇒tan3(π4+θ)+tan3(π4−θ)+3⋅3=27[∵tan(π4+θ)⋅tan(π4−θ)=1]∴tan3(π4+θ)+tan3(π4−θ)=18