Question

sin20⁰ tana sec70⁰≈√3

Answer 1

$sin20\ *\ tan\ a\ *\ sec\ 70= \sqrt{3} \\ \\ sin20\ *\ tan\ a\ *\ \frac{1}{cos\ 70} = \sqrt{3} \\ \\ sin20\ *\ tan\ a\ *\ \frac{1}{sin\ (90-70)} = \sqrt{3} \\ \\ sin20\ *\ tan\ a\ *\ \frac{1}{sin\ 20} = \sqrt{3}$

$tan\ a= \sqrt{3} \\ \\ a=tan^{-1} \sqrt{3}=60^{0}$

Answer 2

$Sin 20\ Tan\ a\ \frac{1}{Cos\ 70}=\sqrt3\\\\tan\ a\ \frac{Sin\ 20}{Sin(90-70)}=\sqrt3\\tan\ a=\sqrt3\\a=\pi/3\ \ or\ \ 4\pi/3\\\\a=n\pi+\pi/3,\ \ n\ is\ any\ integer$