The CSS cos() function is a mathematical function that calculates the cosine of a given angle. The cosine is a trigonometric function that represents the ratio of the adjacent side to the hypotenuse of the right-angle triangle. The cosine of an angle is used to determine the x-coordinate of a point on the unit circle that corresponds to the angle.

Syntax:

width: calc(angle);

Parameters: The function accept one parameters that are described below:

• angle: The angle, expressed in radians, for which the cosine value is to be calculated. It is important to note that CSS uses radians, not degrees, to measure angles. To convert from degrees to radians, you can use the formula: radians = degrees * (π / 180).

Return Value: The function’s return value is the cosine of the given angle, expressed as a floating-point number between -1 and 1.

Example 1: Let’s take an example to understand how the cos() function works.

Output:

 

This code will display a green box of 100×100 pixels on the screen. The position of the box will be calculated using the CSS cos() function, with a result of left: calc(30% + 50px * cos(30deg)); placing the box 50 pixels to the right of the center of the screen.

Example 2: Dynamic Width Based on the Cosine of an Angle.

Output:

 

In this example, the width of the green box is set to be equal to its height multiplied by the cosine of 45 degrees, resulting in a value of approximately 70.7107px.

Supported browsers:

• Firefox 16.0
• Safari 15.4