The trigonometric ratios sine, cosine and tangent are used to calculate angles and sides in right angled triangles. We are now going to extend trigonometry beyond right angled triangles and use it to ...

👉 Learn how to graph a cosine function. To graph a cosine function, we first determine the amplitude (the maximum point on the graph), the period (the distance/time for a complete oscillation), the ...

👉 Learn how to evaluate the cosine of an angle in radians using the sum/difference formulas. To do this, we first express the given angle as a sum or a difference of two (easy to evaluate) angles, ...