The value of tan4° tan43° tan47° tan86° is:

\(\sqrt {3}\)   \(\frac{1}{\sqrt {3}}\) 1 \(\sqrt {2}\)

1

tan4° tan43° tan47° tan86° = (tan4° tan86°)  (tan43° tan47°) *( tan (90-θ) = cotθ,  tanθ cotθ = 1)* = (tan4° cot4°) (tan43° cot43°) = 1 × 1 = 1