Question

Решите уравнение
1+2+4+...+x=255

Answer 1

b1 = 1

b2 = 2

b3 = 4

q = b3/b2 = b2/b1 =2

$\\ s \: = \frac{b1(1 - {q}^{n}) }{1 - q} = \frac{1(1 - {2}^{n} )}{1 - 2} = > \\ 255 = \frac{1 - {2}^{n} }{ - 1} \\ - 255 = 1 - {2}^{n} \\ - 256 = - {2}^{n} \\ {2}^{8} = {2}^{n} \\ n = 8$

b8 = b1 * q ^ (n-1) = 1*2^7 =128