Trigonometric Functions
The trigonometric ratios can also be considered as functions of a variable which is the measure of an angle.
This angle measure can either be given in degrees or radians . Here, we will use radians. Since any angle with a measure greater than radians or less than is equivalent to some angle with measure , all the trigonometric functions are periodic .
The graph of the sine function looks like this:
Note that the domain of the function ) is all real numbers (sine is defined for any angle measure), the range is .
The graph of the cosine function looks like this:
The domain of the function is all real numbers (cosine is defined for any angle measure), the range is .
The graph of the tangent function looks like this:
The domain of the function ) is all real numbers except the values where is equal to , that is, the values for all integers . The range of the tangent function is all real numbers.
The graph of the secant function looks like this:
The domain of the function is again all real numbers except the values where is equal to , that is, the values for all integers . The range of the function is or .
The graph of the cosecant function looks like this:
The domain of the function is all real numbers except the values where is equal to , that is, the values for all integers . The range of the function is or .
The graph of the cotangent function looks like this:
The domain of the function is all real numbers except the values where is equal to , that is, the values for all integers . The range of the function is all real numbers.