[从头学数学] 第159节 反比例函数 小结与复习题

正剧開始：

星历2016年04月03日 09:50:19, 银河系厄尔斯星球中华帝国江南行省。

[project师阿伟]正在和[机器小伟]一起研究[反比例函数 小结与复习题]。

<span style="font-size:18px;">	if (1) {
	
		var r = 20;    
        config.setSector(1,1,1,1);      
        config.graphPaper2D(0, 0, r);    
        config.axis2D(0, 0,180, 1.5);      
        
		//坐标轴设定
        var scaleX = 2*r, scaleY = 2*r;  
        var spaceX = 2, spaceY = 2;   
        var xS = -10, xE = 10;  
        var yS = -10, yE = 10;  
        config.axisSpacing(xS, xE, spaceX, scaleX, 'X');    
        config.axisSpacing(yS, yE, spaceY, scaleY, 'Y');    
            
        var transform = new Transform();    

		//存放函数图像上的点
        var a = [], b = [], c = [], d = [];  
          
		//须要显示的函数说明
		var f1 = 'y=2/x', f2 = 'y=2/|x|', f3 = 'y=-2/x', f4 = 'y=-2/|x|';
		//函数描点
		
		var x = xS;
		
		while (x <= xE) {
			if (Math.abs(x) <= 2) {
				x += 0.25;
			}
			else {
				x += 1;
			}
			
			if (x != 0) {
				//a.push([x, 2/x]);  
				//b.push([x, 2/Math.abs(x)]);  
				//c.push([x, -2/x]);
				d.push([x, -2/Math.abs(x)]);

			}
		}
			
        
		//存放暂时数组
		var tmp = [];
          
        //显示变换
		if (a.length > 0) {
			a = transform.scale(transform.translate(a, 0, 0), scaleX/spaceX, scaleY/spaceY); 
			//函数1
			tmp = [].concat(a);    
			shape.pointDraw(tmp, 'red');    
			tmp = [].concat(a);    
			shape.multiLineDraw(tmp, 'pink');  
			  
			plot.setFillStyle('red');
			plot.fillText(f1, 200, -90, 200);  
		}
		
		if (b.length > 0) {
			b = transform.scale(transform.translate(b, 0, 0), scaleX/spaceX, scaleY/spaceY);  		    
			//函数2
			tmp = [].concat(b);    
			shape.pointDraw(tmp, 'blue');    
			tmp = [].concat(b);    
			shape.multiLineDraw(tmp, '#22CCFF'); 
			
			plot.setFillStyle('blue');
			plot.fillText(f2, 200, -120, 200); 

		}
         
		if (c.length > 0) {
			c = transform.scale(transform.translate(c, 0, 0), scaleX/spaceX, scaleY/spaceY);  
			tmp = [].concat(c);    
			shape.pointDraw(tmp, 'green');    
			tmp = [].concat(c);    
			shape.multiLineDraw(tmp, '#CCFF22');  
			plot.setFillStyle('green');  
			plot.fillText(f3, 200, -150, 200); 
		}
		
		if (d.length > 0) {
			d = transform.scale(transform.translate(d, 0, 0), scaleX/spaceX, scaleY/spaceY);  
			tmp = [].concat(d);    
			shape.pointDraw(tmp, 'orange');    
			tmp = [].concat(d);    
			shape.multiLineDraw(tmp, '#CC8800');  
			plot.setFillStyle('orange');  
			plot.fillText(f4, 200, -180, 200); 
		}

         

	}
	
</span>

本节到此结束，欲知后事怎样，请看下回分解。