1.

If `u=inte^(ax)sin " bx dx" and v=int^(e^(ax))cos " bx dx"`,then `tan^(-1)((u)/(v))+tan^(-1)((b)/(a))` equalsA. bxB. 2 bxC. `b^(2)x^(2)`D. `sqrt(bx)`

Answer» Correct Answer - a
We have, `u=(e^(ax))/(a^(2)+b^(2))( asin bx - b cos bx)`
and `v=(e^(ax))/(a^(2)+b^(2))(a cos bx+b sinbx)`
`:. (u)/(v)=(a sin bx-bcosbx)/(a cosbx+b sinx)`
`rArr (u)/(v)=(sin(bx-theta))/(cos(bx-theta))`, where `a=r costheta,b=r=sinthetaandtantheta=(b)/(a)`
`rArr (u)/(v)=tan(bx-theta)`
`rArr "tan"^(-1)(u)/(v)=bx-"tan"^(-1)(b)/(a)rArr"tan"^(-1)(u)/(v)+"tan"^(-1)(b)/(a)=bx`


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