sum from n=1 to infinity of 1/((0.8)^n)

解答

n = 1 \sum \infty \frac{1}{( 0.8 ) ^{n}}

发散

求解步骤

n = 1 \sum \infty \frac{1}{0. 8 ^{n}}

n = k \sum \infty (a_{n}) = n = 0 \sum \infty (a_{n}) - a_{0} - a_{1} - \dots a_{k - 1}

= n = 0 \sum \infty \frac{1}{0. 8 ^{n}} - \frac{1}{0. 8 ^{0}}

n = 0 \sum \infty \frac{1}{0. 8 ^{n}} =

发散

如果表达式有部分发散，则整个表达式发散

= 发散

\int_{0}^{2} x^{2} 4 - x^{2} d x

t an g e n t f (x) = \frac{- 8 x}{x ^{2} + 1}

l a pl a ce t r an s f or m 3 t + 2

x \to - 2 lim (x^{2} + 2 x - 3)

t an g e n t 4 cos (x)