python中如何用for循环求数字的几何和_python中for循环计算几何级数和的方法

# 参数说明：
# a: 首项
# r: 公比
# n: 项数
<p>a = 1
r = 2
n = 5</p><p>total = 0
for i in range(n):
term = a * (r ** i)  # 计算第i项
total += term        # 累加到总和</p><p>print("几何级数和为:", total)</p><p><span>立即学习</span>“<a href="https://pan.quark.cn/s/00968c3c2c15" style="text-decoration: underline !important; color: blue; font-weight: bolder;" rel="nofollow" target="_blank">Python免费学习笔记（深入）</a>”；</p>

a = 1
r = 2
n = 5
<p>total = 0
current_term = a  # 当前项从首项开始</p><p>for _ in range(n):
total += current_term
current_term *= r  # 下一项 = 当前项 × 公比</p><p>print("几何级数和为:", total)</p><p><span>立即学习</span>“<a href="https://pan.quark.cn/s/00968c3c2c15" style="text-decoration: underline !important; color: blue; font-weight: bolder;" rel="nofollow" target="_blank">Python免费学习笔记（深入）</a>”；</p>

def geometric_sum(a, r, n):
    if r == 1:
        return a * n
    total = 0
    current = a
    for _ in range(n):
        total += current
        current *= r
    return total
<h1>示例调用</h1><p>result = geometric_sum(1, 2, 5)
print(result)  # 输出 31</p>