Question

2的x次方减2的负x次方等于2,求x

Answer 1

2的x次方减2的负x次方等于2,

令X=2^x.

X-1/X=2,

X^2-2X-1=0,

X1=√2+1,

X2=1-√2(不合）.

x=lg2(√2+1)