6.23.3 Can you answer these questions?

6.23.3.1 Simplify Equation with variable unequal to zero

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230846

How can I simplify the following equation with Mathematica assuming z!=0? 
I have the following code: 
... 
[simplifying-expressions]
 

asked by Franz Ferdinand https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74882 1 vote

6.23.3.2 finding primes using chebyshev bias

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230943

Using the problem from my previous question link. For each n, that is n= $10^3$ to $10^6$ with a ten-fold increase, how do I use Chebyshev Bias to display the number of primes (which are in the ... 
[list-manipulation] [prime-numbers]
 

asked by complab56 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74866 1 vote

6.23.3.3 Why does NDSolve not give consistent results?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230784

This is my code: 
... 
[differential-equations] [numerical-integration]
 

asked by S.J.E. Huisman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74858 1 vote