Question

2的x次方＋2的负x次方等于17╱4 求x

Answer 1

x=2

2^x+2^-x=17/4

2^x+1/2^x=17/4

[(2^x)^2+1]/2^x=17/4

(2^x)^2+1=17 或 2^x=4

得：x=2