Basic of Logarithms
easy

If ${{{{\sin }^2}x + 1} \over {2{{\sin }^2}x - 5\sin x + 3}}$=${A \over {(2\sin x - 3)}} + {B \over {(\sin x - 1)}} + C$, then

A

$A = {{13} \over 2}$

B

$A + B + C = 5$

C

$C = 1$

D

$(a)$ and $(b)$ both

Solution

(d) ${\sin ^2}x + 1 = A(\sin x – 1) + B(2\sin x – 3)$

$ + C(\sin x – 1)\,(2\sin x – 3)$

$ \Rightarrow $ $1 = 2C \Rightarrow C = {1 \over 2}$

$0 = A + 2B – 5C,\,1 = – A – 3B + 3C$.

$\therefore A = {{13} \over 2}$, $B = – 2$, $C = {1 \over 2}$, $A + B + C = 5$.

Std 11
Mathematics

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