Solve the product $5\left(1+x^2\right)$
Rewrite the expression $\frac{1}{-2x+5+5x^2}$ inside the integral in factored form
Take the constant $\frac{1}{5}$ out of the integral
We can solve the integral $\int\frac{1}{\left(x-\frac{1}{5}\right)^2+\frac{24}{25}}dx$ by applying integration by substitution method (also called U-Substitution). First, we must identify a section within the integral with a new variable (let's call it $u$), which when substituted makes the integral easier. We see that $x-\frac{1}{5}$ it's a good candidate for substitution. Let's define a variable $u$ and assign it to the choosen part
Now, in order to rewrite $dx$ in terms of $du$, we need to find the derivative of $u$. We need to calculate $du$, we can do that by finding the derivative of the equation above
Substituting $u$ and $dx$ in the integral and simplify
Factor the integral's denominator by $\frac{24}{25}$
Simplify the expression
Solve the integral applying the substitution $v^2=\frac{25u^2}{24}$. Then, take the square root of both sides, simplifying we have
Now, in order to rewrite $du$ in terms of $dv$, we need to find the derivative of $v$. We need to calculate $dv$, we can do that by finding the derivative of the equation above
Isolate $du$ in the previous equation
After replacing everything and simplifying, the integral results in
Solve the integral by applying the formula $\displaystyle\int\frac{x'}{x^2+a^2}dx=\frac{1}{a}\arctan\left(\frac{x}{a}\right)$
Multiplying the fraction by $\arctan\left(v\right)$
Replace $v$ with the value that we assigned to it in the beginning: $\frac{5u}{\sqrt{24}}$
Replace $u$ with the value that we assigned to it in the beginning: $x-\frac{1}{5}$
Simplify the product by distributing $5$ to both terms
As the integral that we are solving is an indefinite integral, when we finish integrating we must add the constant of integration $C$
Try other ways to solve this exercise
Get a preview of step-by-step solutions.
Earn solution credits, which you can redeem for complete step-by-step solutions.
Save your favorite problems.
Become premium to access unlimited solutions, download solutions, discounts and more!