CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
275
You visited us 275 times! Enjoying our articles? Unlock Full Access!
Question

The absolute value of tanπ16+tan5π16+tan9π16+tan13π16 is

Open in App
Solution

Let θ=π168θ=π2
tanπ16+tan5π16+tan9π16+tan13π16=tanθ+tan5θ+tan9θ+tan13θ=tanθ+tan5θ+tan(8θ+θ)+tan(8θ+5θ)=tanθ+tan5θ+tan(π2+θ)+tan(π2+5θ)=tanθ+tan5θcotθcot5θ=tanθcotθ+tan5θcot5θ(cotθtanθ=2cot2θ)=2cot2θ2cot10θ=2[cot2θ+cot(8θ+2θ)]=2[cot2θ+cot(π2+2θ)]=2[cot2θtan2θ]=4cot4θ=4cotπ4=4

Therefore, the absolute value of the expression is 4.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon