Finding large prime factors (number theory)

  • Thread starter Thread starter bremenfallturm
  • Start date Start date
  • Tags Tags
    Factorization Prime
bremenfallturm
Messages
81
Reaction score
13
Homework Statement
Find the prime factorizations of 314000.
Relevant Equations
Unsure - I've tried a couple of different methods as explained in the post
Hello!

I'm asked to factor 314000 by hand. The answer key says that is is ##2^4\cdot 5^3\cdot 157##, but I honestly have no idea how to factor it by hand.

I know that I can check all prime numbers up to ##\sqrt{314000}## but that would not be doable by hand obviously.
I did try to use the method that this video suggests:
(Which basically is: try to divide by 2, try to divide by 3, try to divide by 5, try to divide by 7)
But the problem is that ##157## is a factor.
How can I factor the number by hand?
 
Physics news on Phys.org
Where is the problem?
$$
314000=314\cdot 1000=2\cdot 157 \cdot (10^3)=2\cdot 157\cdot (2\cdot 5)^3=2^4\cdot5^3\cdot 157
$$
 
  • Like
Likes berkeman, renormalize and gmax137
Oh you're right. Sometimes you're just intimidated by a problem I guess. The problem is nowhere now.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top