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Question

Question: The set of real values of x for which \(B = \frac{1}{2}\)is....

The set of real values of x for which B=12B = \frac{1}{2}is.

A

y=Ax+B(x2+1)2=12(1x)(x2+1)2y = \frac{Ax + B}{(x^{2} + 1)^{2}} = \frac{1}{2}\frac{(1 - x)}{(x^{2} + 1)^{2}}

B

5x+6(2+x)(1x)=432+x+1131x\frac{5x + 6}{(2 + x)(1 - x)} = \frac{\frac{- 4}{3}}{2 + x} + \frac{\frac{11}{3}}{1 - x}

C

432(1+x2)+1131x=23(1+x2)1+113(1x)1\frac{\frac{- 4}{3}}{2\left( 1 + \frac{x}{2} \right)} + \frac{\frac{11}{3}}{1 - x} = \frac{- 2}{3}\left( 1 + \frac{x}{2} \right)^{- 1} + \frac{11}{3}(1 - x)^{- 1}

D

None of these

Answer

y=Ax+B(x2+1)2=12(1x)(x2+1)2y = \frac{Ax + B}{(x^{2} + 1)^{2}} = \frac{1}{2}\frac{(1 - x)}{(x^{2} + 1)^{2}}

Explanation

Solution

2=9B2 = 9 - B …..(i)

For log to be defined,

\Rightarrow B=73x+4=A(x1)B(x2)B = 73x + 4 = A(x - 1) - B(x - 2) or \Rightarrow

Now from (i), 12log0.1,x2\frac{1}{2} \leq \log_{0.1},x \leq 2

4=A+2B4 = - A + 2B \Rightarrow …..(ii)

Case (i) A=10,B=7A = 10,B = 7

From (ii), \therefore

\Rightarrow f(x)x+1=φ1(x)+6x+1,f(x)x2=φ2(x)+3x2\frac{f(x)}{x + 1} = \varphi_{1}(x) + \frac{6}{x + 1},\frac{f(x)}{x - 2} = \varphi_{2}(x) + \frac{3}{x - 2}

\Rightarrow f(x)(x+1)(x+2)(x2)=φ(x)+Q(x)(x+1)(x+2)(x2)\frac{f(x)}{(x + 1)(x + 2)(x - 2)} = \varphi(x) + \frac{Q(x)}{(x + 1)(x + 2)(x - 2)}.

Case (ii) Q(x)Q(x)

From (ii), Q(x)(x+1)f(x)(x+1)Q(x)Q(x)(x + 1)f(x)(x + 1)Q(x)

(x2)f(x)(x - 2)f(x); x+2,x + 2,\therefore.