1.

If`alpha=int_0^1(e^9x+3tan^((-1)x))((12+9x^2)/(1+x^2))dxw h e r etan^(-1)`takes only principal values, then the value of `((log)_e|1+alpha|-(3pi)/4)i s`

Answer» Correct Answer - 9
Here , `alpha = int_(0)^(1)e^((9x+3tan^(-1)x))((12+9x^(2))/(1+x^(2)))dx`
Put `9x+3 tan^(-1) x=t`
`rArr (9+(3)/(1+x^(2)))dx = dt`
`:. alpha= int _(0)^(9+3pi//4)e^(t)dt = [e^(t)] _(0)^(9+3pi//4)=e^(9+3pi//4)-1`
`rArr log _(e)|1+alpha|=9+(3pi)/(4)`
` rArr log _(e) | alpha+1|-(3pi)/(4)=9`


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