AUREA
Last Activity: 9 Years ago
Let f(x) be a periodic functon having period T. then solve the equation
f(x+T)=f(x)
the smallest such value of T is the fundamental period of f and Tshould be positive and independent of x
let us take an example:to find the period of sin x
sin(x+T)=sin x
i.e x+T = nπ+(-1)nx
putting n=0 gives T=0
n=1 does not give a value of T independent of x
n=2 gives T=2π and so on
thus least value +ve value of T independent of x is 2π.
there are vsome properties of periodic functions mostly trigonometric which are useful:-
modulus of trignometric functions(sin, cos, tan, cot, sec, cosec) have fund. period π
sinnx, cosnx, cosecnx, secnx have period 2π if n=odd & π if n is even
if f(x) has period T , then kf(ax+b) is periodic having period T/IaI
e.g. period of sin(9x+3)=2π/9
There are more other propreties of perioic functions.