Period Of Trigonometric Functions
November 26th, 2006 . by Vanaja
We know trigonometric functions are periodic functions. Sinx and cos x are periodic functions with period 2? or 360° . But tan and cot remain unchanged when x is increased by ? or 180° .
So, they are periodic functions with period ?.
The general form of the sine function is y = A sinB(x - C) + D
Here, the period is 2?/IBI.
The general form of the cosine function is y = A cosB(x - C) + D
We know cosine functions are identical to the sine functions. So, the period of cosine function is also 2?/IBI.
But for a tangent function. It is ? instead of 2? because the period of tan x is ?.
If the general form of a tangent function is y = A tanB(x - C)+ D,
its period is ?/IBI
There fore, the value of B is the key factor in determining the period of tangent functions. Change in its value changes horizontal stretching. When drawing the graph we have to “stretch” or ;“shrink” the graph horizontally by a factor of B.
Also, the period is unchanged by vertical scaling or shifting or by horizontal shifting.

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