Which of the following integrals cannot be evaluated using a simple substitution?

the integral of 1 divided by the quantity x squared plus 1, dx

the integral of 1 divided by the quantity x squared plus 1, dx

the integral of x divided by the quantity x squared plus 1, dx
(MY ANSWER)

the integral of x cubed divided by the quantity x to the 4th power plus 1, dx

To determine which of the integrals cannot be evaluated using a simple substitution, we need to analyze the complexity and pattern of the integrands.

For the first integral, the integrand is 1/(x^2 + 1). This can be evaluated through a simple substitution, letting u = x^2 + 1, which transforms the integral into ∫(1/u) du.

For the second integral, the integrand is also 1/(x^2 + 1), which is the same as the first integral. Therefore, this integral can also be evaluated using a simple substitution.

For the third integral, the integrand is x/(x^2 + 1). You can try a simple substitution of u = x^2 + 1, but it will not simplify the integral. Therefore, this integral cannot be evaluated using a simple substitution.

For the fourth integral, the integrand is x^3/(x^4 + 1). Although it appears complex, it can be simplified using a simple substitution. Let u = x^4 + 1, which transforms the integral into ∫(1/u) du. Therefore, this integral can also be evaluated using a simple substitution.

Based on our analysis, the third integral, the integral of x/(x^2 + 1), cannot be evaluated using a simple substitution.

Nope.

∫ 1/(x^2+1) dx :: not so simple here. You need x = tanθ

The 2nd is the same, unless there are some groupings you have omitted.

∫ x/(x^2+1) dx :: u = x^2+1
∫ x^3/(x^4+1) dx :: u = x^4+1

woah... 2016...............ah, when life was great... to bad it is 2021...wow, that is a time gap. LORD SAVE OUR SOULS!

BAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHBAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHBAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

BLM +VOTE+ COVID= hope yall have a nice life.