IITJEEONE

 Telangana inter 1st year english model  

r1/bc+r2/ca+r3/ab=1/r-1/2R Topic: properties of triangle Question: r1/bc+r2/ca+r3/ab=1/r-1/2R Answer: given that  r1/bc+r2/ca+r3/ab = 1/r-1/2R LHS: r1/bc+r2/ca+r3/ab 1 ⁄ abc (𝝨a r 1 ) [r1=s. Tan(A/2) a=2S sin (A)] 4RS/4R△ 𝝨sin 2 =S/Δ 𝝨sin 2 A/2 1/r(sin 2 A/2+sin 2 B/2+sin 2 C/2) 1/r((1-cosA)/2+(1-cosB/2)/2+(1-cosC)/2)