This formula is used to calculate the area of a circle.
这个公式用于计算圆的面积。
Example: Functional index on the area of a circle
示例：对圆的面积执行函数索引
This example shows how to create a functional index on the area of a circle.
本示例展示如何对圆的面积创建函数索引。
Next, create an SPL function that returns the area of a circle given its radius.
接着，创建一个spl函数，它将返回给定半径的圆的面积。
This is beneficial when the dataset is large and the frequency of queries that request the area of a circle is high.
如果数据集较大，或者经常发出请求圆面积的查询，那么创建函数索引将有助于提高性能。
One of the problems that has never been solved is that of "squaring the circle." This really means to find the exact area of a circle.
一个一直没有得到解决的问题是，怎样“求圆的面积”。这个问题的真实意思是：求一个圆的精确面积。
In this chapter, we are (finally) going to write fruitful functions. The first example is area, which returns the area of a circle with the given radius.
在本章，我们总算要写一些有返回值的函数了。第一个例子就是一个计算给定半径的圆的面积的函数。
A spotlight lights up only one section of a stage; similarly, "spotsound" creates a circle of sound in on targeted area.
聚光灯只能照亮舞台的一部分；同样，“定点音效”也能把声音投射到指定的区域。
Create a functional index on the area of the circle.
对这个圆形区域创建一个函数索引。
Well, it's just the area of a unit circle.
这就等于一个单位圆的面积。
Let's say that we want to find the area of an ellipse with semi-axes a and b. OK, so that means an ellipse is just like a squished circle.
现在需要计算一个以a，b为半轴的椭圆的面积,其实椭圆就是一个被压扁的圆。
As an example, we'll write a function that takes two points, the center of the circle and a point on the perimeter, and computes the area of the circle.
下面我们写一个函数作为例子，这个函数需要两个点，一个是圆心，一个是圆周上面的点，函数要用来计算这个圆的面积。
In the dark gray gutter to the left of the text area, double-click to create a breakpoint. It looks like a little blue circle, as you can see in Figure 6.
在文本区域左边的深灰色槽中，双击创建一个断点。
Each morning use sunscreen cream to smear a square and a circle area on the back of one's hands.
每天早上用防晒霜在自己的一只手背涂一个方块，在另一只上涂一个圆。
A new analogue analysis model on the inner circle grinding is set by meshing the grinding area of work-piece surface.
借助于工件磨削区域的分割和砂轮表面的离散化处理，建立了一种新的内圆磨削模拟计算模型。
The Icefjord Centre will be located 150 miles north of the Artic Circle in Ilulissat, a UNESCO-protected area on Greenland's western coast.
冰湾中心位于伊卢利萨特的北极圈以北150英里的地方，它是受联合国教科文组织所保护的格陵兰岛西海岸地区。
How to create a marker only drawable into the bounds of the circle area?
如何创建一个标记只冲成圆的面积范围？
The radius of a circle is 4cm, how many square centimeters is its area?
一个圆的半径是4厘米，它的面积是多少平方厘米？
Corner Area: the edge line with the goal line cross, have a dot, radius is 1m, drawing a quarter of circle arc.
角球区：以边线和球门线交叉点为圆点，以1米为半径，向场内各画一段四分之一的圆弧，这个弧内地区叫角球区。
For a centrifugal ballast cleaning machine, the circle section of a centrifugal sieve is an important settling area.
离心筛式道碴清筛机上，离心筛的圆弧段是重要的筛分区段。
It can only be taken from the shooting circle, a roughly semi-circular area in front of the opponents' goal.
只能在射门区内攻进的球才能得分。射门区是对方球门前的一个大致呈半圆形的区域。
This paper took the real estate project of Jin Bi Bazaar as an example, to explore how the real estate project positioned itself in the commercial circle of a certain area.
本文以昆明金碧商城地产项目为例，探索处于整体商圈中的某一地产项目的定位问题。
You are to write a program to find a circle which covers a set of points and has the minimal area. There will be no more than 100 points in one problem.
但是提供了一个思路，枚举的时候如果点非常多，是否可以从直径开始找最小覆盖圆，效率是否会更优？
Apply a Gradient Overlay to the circle and drag the lightest area to the top of the circle, like the image below.
应用渐变叠加的圆圈并拖动最轻的地区，圆的上方，就好像下面的图片。
Requirements: member function respectively, and a friend function to find area and circumference of a circle.
要求：分别用成员函数和友元函数来求圆的面积和周长。
The dot was scaled up to give more of a visual impression, then a temporary circle was used to knock out an area of the shape to give the crescent shape.
这个点被擦除掉可以带来更好的视觉印象，这个临时的圆点用来擦除部分的i的上面的圆点来形成月牙型形状。
The dot was scaled up to give more of a visual impression, then a temporary circle was used to knock out an area of the shape to give the crescent shape.
这个点被擦除掉可以带来更好的视觉印象，这个临时的圆点用来擦除部分的i的上面的圆点来形成月牙型形状。
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