Integration questions for my astoronomy class

Click For Summary
The discussion focuses on integration techniques needed for an astronomy class, specifically integrating from a defined range with a complex function involving Hubble's constant and cosmological parameters. The user expresses confusion about how to approach the integration process, particularly with the given differential equation. A suggested method involves a variable substitution to simplify the integration, referencing trigonometric identities to facilitate the calculation. The conversation emphasizes the importance of understanding the integration steps and transformations to solve such problems effectively. Mastering these integration techniques is crucial for success in astronomy-related coursework.
b_o3
Messages
52
Reaction score
0
Hi, I have to do a lot of integration questions for my astoronomy class but I'm not really sure how to! for example how do u integrate from a number let's say a = 0, to a = 1/(1+z)... and dt = \frac{da}{H_0 \left(\frac{\Omega_{m,0}}{a} + a^2 \Omega_{\Lambda,0}\right)^{\frac{1}{2}}}

I've done a different kind of simple integration but i have no idea how this works,. thanks!
 
Physics news on Phys.org
dt = \frac{da}{H_0 \left(\frac{\Omega_{m,0}}{a} + a^2 \Omega_{\Lambda,0}\right)^{\frac{1}{2}}}

Is this what you mean ?
 
To integrate \frac{du}{(a^2 + b^2 u^2)^{-\frac{1}{2}}}
make the variable change
\frac{bu}{a} = tan v
and remember that
1 + tan^2 v = sec^2 v
 
yest mentz its that one
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 18 ·
Replies
18
Views
1K
Replies
6
Views
3K
Replies
6
Views
1K
Replies
11
Views
1K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
64
Views
5K
  • · Replies 9 ·
Replies
9
Views
772
  • · Replies 3 ·
Replies
3
Views
542