<p>Can anyone show the steps involved in deriving this equation from the friedmann equation with the cosmological constant involved</p>

<p><a href="https://i.sstatic.net/RY4AW.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/RY4AW.jpg" alt="equation of the age of the universe"></a></p>

CC BY-SA 4.0
2018-06-06T18:37:10.190Z
It would help if you (a) used [Mathjax](https://math.meta.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference) for the maths, (b) explained where you got the expression (e.g. link to paper) and (c) explained the symbols (what in this case are $H_D, t_D, \Omega_{\Lambda} and \Omega_m$.  Also try searching Physics SE where similar questions appear.  Thanks.
StephenG - Help Ukraine
CC BY-SA 4.0
2018-06-07T09:17:14.170Z
Please also show what you have done to obtain the solution yourself. The steps should involve 1) neglect everything but matter and dark energy from the Friedmann equation, 2) integrate the equation over time, 3) approximate $a(t)$ at late times ("late" meaning after matter-$\Lambda$ equality), and 4) isolate $t_0$
pela
<universe><cosmology><age>
How to derive the equation for the age of a flat universe with a positive cosmological term?
user193469
# How to derive the equation for the age of a flat universe with a positive cosmological term?

(Asked by: username_0 on 2018-06-05)

Can anyone show the steps involved in deriving this equation from the friedmann equation with the cosmological constant involved

[![equation of the age of the universe](https://i.sstatic.net/RY4AW.jpg)](https://i.sstatic.net/RY4AW.jpg)

**Tags:** universe, cosmology, age

> **Comments:**
> **username_1**: It would help if you (a) used [Mathjax](https://math.meta.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference) for the maths, (b) explained where you got the expression (e.g. link to paper) and (c) explained the symbols (what in this case are $H_D, t_D, \Omega_{\Lambda} and \Omega_m$.  Also try searching Physics SE where similar questions appear.  Thanks.  
> **username_2**: Please also show what you have done to obtain the solution yourself. The steps should involve 1) neglect everything but matter and dark energy from the Friedmann equation, 2) integrate the equation over time, 3) approximate $a(t)$ at late times ("late" meaning after matter-$\Lambda$ equality), and 4) isolate $t_0$  

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## 0 answers

