7 ms·
You definitely don't need to know any of that background to be able to arrive at the answer. To fully understand everything maybe, but all it takes is: a = x^1
by rak1507 1y ago
You definitely don't need to know any of that background to be able to arrive at the answer. To fully understand everything maybe, but all it takes is:
a = x^1 + x^4 + x^7 + ... = x(1 + x^3 + x^6 + ...) = x/(1-x^3)
a + a^3 + a^5 + ... = a(1 + a^2 + a^4 + ...) = a/(1-a^2)
Substitute + simplify.
I don't think this is beyond a (fairly smart) elementary school student.