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

[latex]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 [/latex]