IIT JEE , AIEEE Forum - Mathematics , Trignometry

sriram.a

Let a,b,c be the sides of a $\Delta$ ABC. If a^2+b^2=2007c^2,then value of

phanikrishna

answer is a)1003

phanikrishna

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ramkumar_november

$sinA=\frac{a}{2R}$

$cosA=\frac{b^2+c^2-a^2}{2bc}$

$cotA=\frac{cosA}{sinA}=\frac{2R(b^2+c^2-a^2)}{2abc}$

$cotA=\frac{b^2+c^2-a^2}{4\bigtriangleup}$

similarly

$cotB=\frac{a^2+c^2-b^2}{4\bigtriangleup}$

$cotC=\frac{a^2+b^2-c^2}{4\bigtriangleup}$

$\frac{cotC}{cotA+cotB}=\frac{a^2+b^2-c^2}{b^2+c^2-a^2+a^2+c^2-b^2}$

$\frac{cotC}{cotA+cotB}=\frac{a^2+b^2-c^2}{2c^2}$

$\frac{cotC}{cotA+cotB}=\frac{2007c^2-c^2}{2c^2}$

$\frac{cotC}{cotA+cotB}=1003$

PS: please type the question properly without any errors..... you have typed cotA/(cotB+cotA)