如何使用 PHP 中的 log() 获取曲线上的点？
我有一个想要复制的图表：
我有以下 PHP 代码：
$sale_price = 25000;
$future_val = 5000;
$term = 60;
$x = $sale_price / $future_val;
$pts = array();
$pts[] = array($x,0);
for ($i=1; $i<=$term; $i++) {
$y = log($x+0.4)+2.5;
$pts[] = array($i,$y);
echo $y . " <br>\n";
}
如何使代码工作给我沿下线（黄色和蓝色区域之间）的点？不需要很精确，稍微接近即可。
公式是：
-ln(x+.4)+2.5
我通过使用在线函数绘图器 http://www.livephysicals.com/
提前致谢！！
I have a graph I am trying to replicate:
I have the following PHP code:
$sale_price = 25000;
$future_val = 5000;
$term = 60;
$x = $sale_price / $future_val;
$pts = array();
$pts[] = array($x,0);
for ($i=1; $i<=$term; $i++) {
$y = log($x+0.4)+2.5;
$pts[] = array($i,$y);
echo $y . " <br>\n";
}
How do I make the code work to give me the points along the lower line (between the yellow and blue areas)? It doesn't need to be exact, just somewhat close.
The formula is:
-ln(x+.4)+2.5
I got that by using the Online Function Grapher at http://www.livephysics.com/
Thanks in advance!!
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X 值应该
是您已分配给
$i的贷款期限。另外，为什么你的贷款期限最大值是60？你把年换算成月了吗？确保方程相应地改变。
但不太确定你的方程的有效性。查看图表： http ://www.wolframalpha.com/input/?i=y+%3D+ln%28x+%2B+0.4%29+%2B+2.5
Should be
X values are the loan term, which you have assigned to
$i.Also, why is your loan term max value 60? Did you convert years to months? Make sure the equation is changed accordingly.
Not quite sure of the validity of your equation though. Check out graph: http://www.wolframalpha.com/input/?i=y+%3D+ln%28x+%2B+0.4%29+%2B+2.5