Trigonometry Workbook For Dummies
Book image
Explore Book Buy On Amazon

When you multiply a trig function by a negative number, all the output values are reversed in sign. The positive values become negative, and the negative values become positive. The effect that this operation has on the graph is that it appears to have a reflection or flip over a horizontal line.

The graph of <i>y</i> = –sin <i>x</i> is the mirror image of <i>y</i> = sin <i>x</i>.
The graph of y = –sin x is the mirror image of y = sin x.

For example, the figure shows the graph of y = –sin x compared to y = sin x. See how the two graphs compare? The original graph appears to be flipped over the x-axis.

About This Article

This article is from the book:

About the book author:

Mary Jane Sterling taught algebra, business calculus, geometry, and finite mathematics at Bradley University in Peoria, Illinois, for more than 30 years. She is the author of several For Dummies books, including Algebra Workbook For Dummies, Algebra II For Dummies, and Algebra II Workbook For Dummies.

This article can be found in the category: