Drawing a Tangent Line on a Graph in Microsoft Excel
- Create a scatter plot graph in Excel by selecting the data you want to plot and clicking on the "Insert" tab in the ribbon. Then, choose "Scatter" from the chart options.
- Right-click on the data point where you want to draw the tangent line. Select "Add Trendline" from the drop-down menu.
- In the "Format Trendline" window that appears, select the "Options" tab. Check the box next to "Display Equation on chart" and "Display R-squared value on chart."
- Click on the "Line" tab and select "Linear" as the trendline type. Then, click "Close" to exit the window.
- Right-click on the trendline and select "Format Trendline" again. In the "Line Style" tab, change the "Dash Type" to "Long Dash" or "Dash-Dot" to make the line more visible.
- To draw the tangent line, use the equation displayed on the chart. The slope of the line is the coefficient of the x-term in the equation. Choose a point on the line and use the point-slope formula to find the equation of the tangent line. Then, plot the tangent line on the graph using the same x-values as the original data.
That's it! You now have a tangent line on your Excel graph.