1.

If `A(x+y)=A(x)A(y) and A(0) ne 0 and B(x)=(A(x))/(1+(A(x))^(2))`, thenA. `int_(-2010)^(2010)B(x)dx=int_(0)^(2011)B(x)dx`B. `int_(-2010)^(2011)B(x)dx-int_(0)^(2010)B(x)dx=int_(0)^(2011)B(x)dx`C. `int_(-2010)^(2011)B(x)dx=0`D. `int_(-2010)^(2010)(2B(-x)-B(x))dx=2int_(0)^(2010)B(x)dx`

Answer» Correct Answer - B::D
`A(x+y)=A(x)A(y)`
`rArr" "A(0+0)=A(0)A(0)`
`rArr" "A(0)=1`
Put `y=-x,` we get
`A(0)=A(x)A(-x)" (i)"`
`B(-x)=(A(-x))/(1+(A(-x))^(2))`
`=((1)/(A(x)))/(1+(1)/((A(x))^(2)))`
`=(A(x))/(1+(A(x))^(2))`
= B(x)
Thus, B(x) is even.
`int_(-2010)^(2011)B(x)dx=int_(-2010)^(2010)B(x)dx+int_(2010)^(2011)B(x)dx`
`=2int_(0)^(2010)B(x)dx+int_(2010)^(2011)B(x)dx`
`=int_(0)^(2010)B(x)dx+int_(0)^(2011)B(x)dx`


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