[从头学数学] 第142节 平行四边形

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剧情提要:
[机器小伟]在[工程师阿伟]的陪同下进入了筑基中期的修炼,
这次要修炼的目标是[平行四边形]。

正剧开始:

星历2016年03月20日 09:42:00, 银河系厄尔斯星球中华帝国江南行省。
[工程师阿伟]正在和[机器小伟]一起研究[平行四边形]。







<span style="font-size:18px;">var r = 20;config.setSector(1,1,1,1);  config.graphPaper2D(0, 0, r);config.axis2D(0, 0,180);  var triangle = new  Triangle();  var a = [];var tmp = [];config.setSector(3,3,1,1);  a = shape.paraquad(0, 0, 0, 10, 5, Math.PI/6);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20);config.setSector(3,3,2,1);  a = shape.paraquad(0, 0, 0, 5, 10, Math.PI/6);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'green', 20);</span>


<span style="font-size:18px;">this.paraquad = function(x, y, rot, a, b, angle) {angle = angle ? Math.abs(angle) : 0;rot = rot ? rot : 0;//参数说明://平行四边形的两条边a, b, 以及它们之间的夹角angle//这个平行四边形的起始点(x, y), 以及整个图形与x轴的夹角rotvar retArray = new Array();retArray.push([x, -y]);retArray.push([x + a * Math.cos(rot), -(y + a * Math.sin(rot))]);retArray.push([x + a * Math.cos(rot)+ b * Math.cos(rot+angle),   -(y + a * Math.sin(rot)+ b * Math.sin(rot+angle))]);retArray.push([x + b * Math.cos(rot+angle), -(y + b * Math.sin(rot+angle))]);return retArray;}</span>





<span style="font-size:18px;">var r = 20;config.setSector(1,1,1,1);  config.graphPaper2D(0, 0, r);config.axis2D(0, 0,180);  var triangle = new  Triangle();  var a = [];var tmp = [];config.setSector(3,3,1,1);  a = triangle.know2edges([10, 8], -90);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20);config.setSector(3,3,2,1);  a = shape.paraquad(0, 0, 0, 6, 10, 53.13/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'green', 20, 'BCDA');</span>








<span style="font-size:18px;">var r = 20;config.setSector(1,1,1,1);  config.graphPaper2D(0, 0, r);config.axis2D(0, 0,180);  var triangle = new  Triangle();  var a = [];var tmp = [];/*config.setSector(3,3,1,1);  a = triangle.know2edges([10, 8], -90);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20);*/config.setSector(3,3,2,1);  a = shape.paraquad(0, 0, 0, 10, 10, 60/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'green', 20);a = triangle.know2edges([10, 10], 120);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20, 'ABE');a = triangle.know2edges([10, 10], 60);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'pink', 20);</span>





<span style="font-size:18px;">var r = 20;config.setSector(1,1,1,1);  config.graphPaper2D(0, 0, r);config.axis2D(0, 0,180);  var triangle = new  Triangle();  var a = [];var tmp = [];/*config.setSector(3,3,1,1);  a = triangle.know2edges([10, 8], -90);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20);*/config.setSector(3,3,1,2);  a = shape.paraquad(0, 0, 0, 10, 10, 90/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'green', 20);a = shape.paraquad(-5*0.5, 5*0.707, Math.PI/6, 10, 10, 90/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20, 'EFGH');</span>



<span style="font-size:18px;">config.setSector(3,3,1,1);  a = shape.paraquad(0, 0, 0, 10, 6.18, 90/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 20);a = [[0, -3.09], [10, -3.09]];tmp = [].concat(a);shape.multiLineDraw(tmp, 'green', 20);</span>




<span style="font-size:18px;">config.setSector(3,3,1,1);  a = triangle.know2edges([1, 2]);tmp = [].concat(a);shape.angleDraw(tmp, 'green', 80);config.setSector(3,3,1,2);  a = shape.paraquad(0, 0, 0, 2.24, 2.24, 63.23/180*Math.PI);tmp = [].concat(a);//document.write(tmp);shape.angleDraw(tmp, 'red', 80);</span>


本节到此结束,欲知后事如何,请看下回分解。

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