求定义域(那个是X...)2.已知f(x)=a^x+a^-x, 且 f(1)=a+a^-1=4 则f(0)+f(2)=0 选什么A.18 B.16 C.14 D.12
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![求定义域(那个是X...)2.已知f(x)=a^x+a^-x, 且 f(1)=a+a^-1=4 则f(0)+f(2)=0 选什么A.18 B.16 C.14 D.12](/uploads/image/z/6972679-55-9.jpg?t=%E6%B1%82%E5%AE%9A%E4%B9%89%E5%9F%9F%EF%BC%88%E9%82%A3%E4%B8%AA%E6%98%AFX...%EF%BC%892.%E5%B7%B2%E7%9F%A5f%28x%29%3Da%5Ex%2Ba%5E-x%2C+%E4%B8%94++f%281%29%3Da%2Ba%5E-1%3D4+%E5%88%99f%280%29%2Bf%282%29%3D0++%E9%80%89%E4%BB%80%E4%B9%88A.18++++++++++++++B.16+++++++++++++++C.14++++++++++++++D.12)
求定义域(那个是X...)2.已知f(x)=a^x+a^-x, 且 f(1)=a+a^-1=4 则f(0)+f(2)=0 选什么A.18 B.16 C.14 D.12求定义域(那个是X...)
2.已知f(x)=a^x+a^-x, 且 f(1)=a+a^-1=4 则f(0)+f(2)=0 选什么
A.18 B.16 C.14 D.12
求定义域(那个是X...)2.已知f(x)=a^x+a^-x, 且 f(1)=a+a^-1=4 则f(0)+f(2)=0 选什么A.18 B.16 C.14 D.12
1、3-(1/3)^x≥0,(1/3)^x≤3,3^-x≤3,-x≤1,x≥-1.
2、f(0)=2,f(2)=[f(1)]^2-2=4^2-2=14,f(0)+f(2)=16,选B
1.3-(1/3)x>=0 所以x>=-1
2.b
3-(1/3)^x≥0 => (1/3)^x ≤3 => 1/3^x≤3 => 1≤3^(1+x) => 0≤1+x =>x≥-1 =>定义域为[-1,+∞) f(0)=1+1=2 f(1)=a...
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3-(1/3)^x≥0 => (1/3)^x ≤3 => 1/3^x≤3 => 1≤3^(1+x) => 0≤1+x =>x≥-1 =>定义域为[-1,+∞) f(0)=1+1=2 f(1)=a+1/a =4 f(2)=a^2+1/a^2 =(a+1/a)^2 - 2 = f(1)^2-2 =4^2-2=14 =>f(0)+f(2)=2+14=16 =>选B
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