General solution of tanθ+tan4θ+tan7θ=tanθtan4θ tan7θ is
θ=nπ12, where n∈Z
θ=nπ9, where n∈Z
θ=nπ+π12, where n∈Z
none of these
From the given equation, we have
or tanθ+tan4θ1−tanθtan4θ=−tan7θor tan(θ+4θ)=−tan7θor tan5θ=tan(−7θ)⇒5θ=nπ−7θor θ=nπ/12, where n∈Z, but n≠6,18,30,…