Question

已知y=1/2{e^x–e^(-x)},试用含y的式子表示x

Answer 1

令u=1/2 (e^x+e^(-x)) >0

y+u=e^x

u-y =e^(-x)

u^2-y^2=1 ===>u= 根(y^2+1)

那么 x =ln(y+u)= ln （y+根（y^2+1))