Question

Let $P$ be the set of $42^{\text{nd}}$ roots of unity, and let $Q$ be the set of $70^{\text{th}}$ roots of unity. How many elements do $P$ and $Q$ have in common

Answer 1

Answer:

The answer to the given question can be defined as follows:

Step-by-step explanation:

$\to GCF(42, 70) = 7$

Therefore, the common roots of unity were  

$\to e^{\pm i 2\pi \frac{k}{7}}\\\\\ where \\ \\ k=0,1,...... 6$

That's why the  answer is 14 for these