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An Introduction to Statics

Accuracy and Approximation in Calculations

Description

Accuracy and approximation are important in calculations, especially in engineering. Accuracy means how close a measured value is to the true or actual value. Repeated measurements are often used in engineering mechanics to help make results more precise and accurate.

The accuracy of a solution d...

Transcript

在工程计算中,使用精度、极限和近似来表示一个数值。

考虑两个不同尺寸的方形块。通过将它们的数值四舍五入到基于有效数字的最接近值,可以得到其面积的准确数值。

考虑一个底面半径为 r、高为 h 的正圆锥。若在距其顶点距离为 x 处对该圆锥进行圆形截切,使得所截取的微元具有  厚度 Δx,即可确定其体积。

通过对 Δv 取 dv 的极限,对 Δx 取 dx 的极限,并忽略高阶微分项,可得到体积的表达式。

考虑一段弧 AB,其在点 O 处所张的角很小。该弧长可近似为一个直角三角形的底边。

如果斜边的长度为1,则弧长等于sin θ,约等于θ。此外,cos θ也约等于1。

当角度为1度时,sin θ 和 tan θ...

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