Question

Вычислите
1/2+1/4+1/8+...
1-3/4+9/16+...

Answer 1

$1/2+1/4+1/8+...= frac{1/2}{1-(1/4:1/2)} = frac{1/2}{1-1/2}= frac{1/2}{1/2}=1\\1-3/4+9/16+...= frac{1}{1-(-3/4:1)}= frac{1}{1+3/4}= frac{1}{7/4}=4/7$