Finding N: Logarithmic Approach Needed

[Fairy111]

Homework Statement

I need to find N:

{[pi^(N+1)] / (N+1)!} . {1/2^N} <= 10^-5

Homework Equations

The Attempt at a Solution

I'm really struggling with this, i think taking logs is involved, but i can't seem to find a value of N.

Any help?

 

[Dick]

The expression decreases with increasing N. You basically want to evaluate it for various values of N until you figure out where it starts going below 10^(-5). You can only estimate log(n!) and the estimate doesn't lead to anything you can really solve.

 

[Office_Shredder]

Do you need to find any N, or the smallest such N?

 

[Fairy111]

I need to find what N needs to be bigger or equal to.

 

[Dick]

Then just try some integer values for N. N doesn't have to be very big.