Basic of Logarithms
easy

${1 \over {x({x^2} + 1)}} = {A \over x} + {{Bx + C} \over {({x^2} + 1)}}$, then $(A,\,B,\,C) = $

A

$(1, \,-1,\, 0)$

B

$( - 1,\,0,\, - 1)$

C

$(0,\,1,\,1)$

D

None of these

(IIT-1995)

Solution

(a) $A({x^2} + 1) + (Bx + C)x = 1$

For $x = 0,\,A = 1$ and for $x = i$, $ – B + Ci = 1$

$ \Rightarrow B = – 1,\,C = 0$ $ \Rightarrow $ $(A,B,C) = (1,\, – 1,\,0)$.

Std 11
Mathematics

Similar Questions