常见函数绘图 正余弦，幂指对，分段函数，傅立叶-java function plotter

function plotter for java

某公司上半年产品销售状况是：计算机50 、打印机20 、绘图机10 图形扫描仪5 、打印纸10 、硬盘销售5 ，绘制饼状图-Product sales in the first half of a company are: 50 of the computer, printer, 20 , 10 graphics plotter scanner, 5 , 10 paper, 5 of hard drive sales, to draw a pie chart