Integrate {x3+1/(whole root over)x2+x}dx

  • Thread starter Thread starter perfectibilis
  • Start date Start date
  • Tags Tags
    Integrate
Click For Summary
The discussion revolves around the integration of the expression {x^3+1/(whole root over)x^2+x}dx, with participants clarifying the intended form of the integrand. The consensus is to interpret it as ∫(x^3+1)/√(x^2+x)dx. To tackle the integration, the recommended approach involves completing the square in the denominator and applying trigonometric substitution techniques. Participants also emphasize the importance of correctly factoring x^3 + 1 as (x + 1)(x^2 - x + 1). The conversation highlights the need for precision in mathematical notation to ensure accurate integration methods.
perfectibilis
Messages
4
Reaction score
0
Integrate the following--->
{x3+1/(whole root over)x2+x}dx
 
Physics news on Phys.org
Do you mean \int \frac{x^3+1}{\sqrt{x^2+x}}\,dx or \int \left(x^3+\frac{1}{\sqrt{x^2+x}}\right)dx?

Either way, the best thing to do is to start by completing the square in the denominator, then using a bunch of trig substitution stuff.
 
x3+13=(x+1)(x2-x+1)
x2+x=x(x+1)

Is it enough help?
 
Last edited:
Дьявол said:
x3+13=(x+1)(x2+x+1)
x2+x=x(x+1)
Actually, x3 + 1 = (x + 1)(x2 - x + 1).

In any case, we still don't know exactly what the integrand is.
 
foxjwill said:
Do you mean \int \frac{x^3+1}{\sqrt{x^2+x}}\,dx or \int \left(x^3+\frac{1}{\sqrt{x^2+x}}\right)dx?

Either way, the best thing to do is to start by completing the square in the denominator, then using a bunch of trig substitution stuff.

I mean the first image.
 
Mark44 thanks for the correction.

perfectibilis start by writing x3+1 with

\sqrt{(x+1)^2(x^2-x+1)^2}
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

  • · Replies 8 ·
Replies
8
Views
4K
Replies
3
Views
2K
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
3
Views
2K
  • · Replies 105 ·
4
Replies
105
Views
6K
  • · Replies 54 ·
2
Replies
54
Views
14K
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K