Evaluate the infinite geometric series 0.4 + 0.036 + 0.0000324 + ... Express your answer as a fraction with integer numerator and denominator.
Since we have\(r = .036 / .4 = 36 / 400 = 9 /100 = .09 \), our answer is
\(.4 / [ 1 -.09] = .4 / .91 = 40 /91\)