if a cosφ=b cosθ then show that atanθ+btanφ=(a+b) tan$\frac{{\mathrm{\theta}} + {\mathrm{\phi}}}{2}$
if a cosφ=b cosθ then show that atanθ+btanφ=(a+b) tan$\frac{{\mathrm{\theta}} + {\mathrm{\phi}}}{2}$ if a cosφ=b cosθ then show that atanθ+btanφ=(a+b) tan$\frac{{\mathrm{\theta}} …