Mathematics - Properties of Triangle Question with Solution | TestHub

Let $\mathrm{AD},\mathrm{BE},\mathrm{CF}$ be the length of internal bisectors of angles $\mathrm{A},\mathrm{B},\mathrm{C}$ of triangle ABC . Show that the harmonic mean of $\mathrm{AD}\sec \frac{\mathrm{A}}{2}\cdot \mathrm{BE}\sec \frac{\mathrm{B}}{2},\mathrm{CFsec}\frac{\mathrm{C}}{2}$ is the harmonic mean of the sides of the triangle