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Evaluate the integral: `int (-19)/(x^2 sqrt(x^2+81)) dx`
(A) Which trig substitution is correct for this integral?
(B) Which integral do you obtain after substituting for `x` and simplifying?
Note: to enter `theta`, type the word theta.
`int`
`d theta`
(C) What is the value of the above integral in terms of `theta`?
`+ C`
(D) What is the value of the original integral in terms of `x`?
`+ C`
`x=9 tan(theta)`
`-19/81 cot(theta) csc(theta)`
`19/81 csc(theta)`
`19/81 sqrt(x^2+81)/x`