Adding trendline in scatter chart

Created using FusionCharts Suite XT - www.fusioncharts.com

HTML

<script src="http://static.fusioncharts.com/code/latest/fusioncharts.js"></script>
<script src="http://static.fusioncharts.com/code/latest/fusioncharts.charts.js"></script>
<script src="http://static.fusioncharts.com/code/latest/themes/fusioncharts.theme.fint.js"></script>
<!-- Scatter chart example -->
<div id="chart-container">FusionCharts will render here</div>

JavaScript

FusionCharts.ready(function () {
    var tempVsSalesChart = new FusionCharts({
        type: 'scatter',
        renderAt: 'chart-container',
        width: '600',
        height: '350',
        dataFormat: 'json',
        dataSource: {
            "chart": {
                "caption": "Sales of Beer & Ice-cream vs Temperature",
                    "subCaption": "Los Angeles Topanga",
                    "baseFont": "Helvetica Neue,Arial",
                    "captionFontSize": "14",
                    "subcaptionFontSize": "14",
                    "axis":"log",
                    "logBase":"1",
                    "subcaptionFontBold": "0",
                    "xAxisName": "Average Day Temperature",
                    "yAxisName": "Sales (In USD)",
                    "xAxisMinValue": "23",
                    "xAxisMaxValue": "95",
                    "yNumberPrefix": "$",
                    "xNumberSuffix": "&deg; F",
                    "showBorder": "0",
                    "paletteColors": "#0075c2,#1aaf5d,#f2c500",
                    "bgcolor": "#ffffff",
                    "canvasBgColor": "#ffffff",
                    "showShadow": "0",
                    "showCanvasBorder": "0",
                    "usePlotGradientColor": "0",
                    "legendBorderAlpha": "0",
                    "legendShadow": "0",
                    "showAxisLines": "1",
                    "showAlternateHGridColor": "0",
                    "showAlternateVGridColor": "0",
                    "divlineThickness": "1",
                    "divLineIsDashed": "1",
                    "divLineDashLen": "1",
                    "divLineGapLen": "1",
                    "showValues": "0",
                    "use3dlighting": "0",
                    "showYAxisLine": "1",
                    "yAxisLineThickness": "1",
                    "yAxisLineColor": "#999999"
            },
                "dataset": [{
                "seriesname": "Ice Cream",
                   ...