试估算1.334·1.503

解:

1.334=1.0005· $\frac{4}{3}$

1.503=1.002· $\frac{3}{2}$

$1.0005·1.002\approx1+0.0005+0.002=1.0025$

$1.334·1.503\approx1.0025·\frac{4}{3}·\frac{3}{2}=2.005$

已知ln(3)=1.098612, 试计算[ln(3)]²

解

ln(3)=1.098612=1.1−0.001388

$\ln^{2}(3)\approx1.21-0.002776=1.207224\approx1.207$