[从头学数学] 第168节 基本初等函数(1)

剧情提要：
[机器小伟]在[工程师阿伟]的陪同下进入了结丹初期的修炼，
这次要修炼的目标是[基本初等函数(1)]。

正剧开始：

星历2016年04月09日 08:40:48, 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[基本初等函数(1)]。

<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);        
          
        //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 = [];    
            
        //需要显示的函数说明  
        var f1 = 'y=2^x', f2 = 'y=(1/2)^x', f3 = 'y=(1/3)^x', f4 = 'y=3^x';  
        //函数描点  
        for (var x = xS; x <= xE; x+=1) {    
            if (x != 0) {  
                a.push([x, Math.pow(2, x)]);    
				b.push([x, Math.pow(1/2, x)]);
				c.push([x, Math.pow(1/3, x)]);
				d.push([x, Math.pow(3, x)]);

            }  
        }    
            
        //存放临时数组  
        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, 100, -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, 100, -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, 100, -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, 100, -180, 200);   
        }  
  
           
  
    } </span>

<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);        
          
        //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 = [], e = [];    
            
        //需要显示的函数说明  
        var f1 = 'y=10^(x)', f2 = 'y = logx', f3 = 'y=x', f4 = 'y=e^x',
			f5 = 'y = ln(x)';
        //函数描点  
        for (var x = xS; x <= xE; x+=0.3) {    
            if (x != 0) {  
                a.push([x, Math.pow(10, x)]);  
				b.push([x, Math.log(x)]); 
				c.push([x, x]);
				d.push([x, Math.pow(Math.E, x)]);
				e.push([x, Math.log(x)/Math.LOG10E]);



            }  
        }    
		
		//document.write(a+'<br/>');
        
		
        //存放临时数组  
        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, 100, -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, 100, -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, 100, -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, 100, -180, 200);   
        }  
  
        if (e.length > 0) {  
            e = transform.scale(transform.translate(e, 0, 0), scaleX/spaceX, scaleY/spaceY);    
            tmp = [].concat(e);      
            shape.pointDraw(tmp, 'purple');      
            tmp = [].concat(e);      
            shape.multiLineDraw(tmp, 'purple');    
            plot.setFillStyle('purple');    
            plot.fillText(f5, 100, -60, 200);   
        }  
  
    } </span>

<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);        
          
        //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 = [], e = [];    
            
        //需要显示的函数说明  
        var f1 = 'y=log_[2]x', f2 = 'y=log_[1/2]x', f3 = 'y=2^x', f4 = 'y=(1/2)^x',
			f5 = 'y = x';
        //函数描点  
        for (var x = xS; x <= xE; x+=0.3) {    
            if (x != 0) {  
                a.push([x, Math.log(x)/Math.log(2)]);  
				b.push([x, Math.log(x)/Math.log(1/2)]); 
				c.push([x, Math.pow(2, x)]);
				d.push([x, Math.pow(1/2, x)]);
				e.push([x, x]);


            }  
        }    
            
        //存放临时数组  
        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, 100, -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, 100, -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, 100, -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, 100, -180, 200);   
        }  
  
        if (e.length > 0) {  
            e = transform.scale(transform.translate(e, 0, 0), scaleX/spaceX, scaleY/spaceY);    
            tmp = [].concat(e);      
            shape.pointDraw(tmp, 'purple');      
            tmp = [].concat(e);      
            shape.multiLineDraw(tmp, 'purple');    
            plot.setFillStyle('purple');    
            plot.fillText(f5, 100, -60, 200);   
        }  
  
    } 
	</span>

本节到此结束，欲知后事如何，请看下回分解。