Write the expression as the sine, cosine, or tangent of an angle?

Question

tan 4x+tan x/1-tan4x tan x

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Answer 1 · 2017-06-07T08:01:37

#(tan4x+tanx)/(1-tan4xtanx)=tan(5x)#

This uses the formula for tangent of sum of two angles as

#tan(A+B)=(tanA+tanB)/(1-tanAtanB)#

Hence #(tan4x+tanx)/(1-tan4xtanx)# can be written as

#tan(4x+x)# i,e, #tan(5x)#