“微信扫一扫”进入题库练习及模拟考试
高中数学必修 第一册（648题）
已知
①
知识点：第四章 指数函数与对数函数
参考答案：①\(\because {({a^{\tfrac{1}{2}}} + {a^{ - \tfrac{1}{2}}})^2} = 9\)
\(\therefore a + {a^{ - 1}} + 2 = 9\)
\(\therefore a + {a^{ - 1}} = 7\)
“微信扫一扫”进入题库练习及模拟考试
已知
①
参考答案：①\(\because {({a^{\tfrac{1}{2}}} + {a^{ - \tfrac{1}{2}}})^2} = 9\)
\(\therefore a + {a^{ - 1}} + 2 = 9\)
\(\therefore a + {a^{ - 1}} = 7\)