# Graph of a trigonometric function

The graph of a trigonometric function are used commonly used in areas of science and engineering. They are used in making models for many natural and mechanical phenomenon like waves, growth of plants and animals etc. The graph of a trigonometric function are periodic. For example,sine and cosine functions are periodic with period 2π, while tangent and cotangent functions are periodic functions with period π. We know that if f(x) is a periodic function with period 'T' and a > 0, then
f(bx + c) is a periodic function with period T/b.
Therefore, a sin(bx + c) and cos(bx) are periodic functions with period $\frac{2π}{b}$. The graph of a periodic function with period 'T' is to be drawn in a given interval, then it is sufficient to draw its graph if and only in an interval of length 'T'. Because once it is drawn in one such interval, it can be easily completely by repeating it over the intervals of lengths 'T'.
The amplitude of a function is defined as the greatest numerical value with it can attain.

## Graph of a trigonometric function

In this section, you will learn details about the graphs of
1) y = a sin(x) and y = a cos(x) and here we will define the amplitude.
2) y = a sin(bx) and y = a cos(bx), here we introduces the period of trigonometric graphs.
3) y = a sin(bx + c ) and y = a cos(bx + c), in this type of graphs we will explain you about the phase shift of a trigonometric curve.
There are some more graphs such as tan(x),sec(x),csc(x) and cot(x) which are not commonly used.