Indefinite integral are written in the form of `int f(x) dx = F(x) +C`
where: `f(x)` as the integrand
`F(x)` as the anti-derivative function
`C` as the arbitrary constant known as constant of integration
To evaluate the given integral problem: `int 1/(t(1+(ln(t))^2)) dt` , we may apply u-substitution by letting: `u =ln(t)` then `du = 1/t dt` .
Plug-in `u =ln(t)` and `du= 1/tdt` on `int 1/(t(1+(ln(t))^2)) dt` , the integral becomes:
`int 1/(t(1+(ln(t))^2)) dt =int1/(1+(ln(t))^2) *1/t dt`
`=int1/(1+u^2) du`
From the integration table, we have indefinite integration formula for rational function as: `int 1/(1+x^2) dx=arctan(x) +C` . The `int 1/(1+x^2)dx ` resembles the format of `int 1/(1+u^2) du ` where " u" corresponds to "x" .
This is our clue that we may apply the aforementioned formula for rational function.
We get: `int1/(1+u^2) du= arctan(u) +C` .
Plug-in `u =ln(t)` on `arctan(u) +C` , we get the indefinite integral as:
`int 1/(t(1+(ln(t))^2)) dt= arctan(ln(t))+C`
Comments
Post a Comment