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**Dharshi****Member**- Registered: 2006-10-31
- Posts: 56

Which of the following functions is non periodic ?

(a) f(x) = {x}, the fractional part of the number x

(b) f(x) = cot(x + 7)

(c) f(x) = 1 sin^2x/(1 + cotx) cos^2x/(1 + tanx)

(d) f(x) = x + sinx

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**Stanley_Marsh****Member**- Registered: 2006-12-13
- Posts: 345

Here a method , assume k are their period. Check out whether the equation F(x)=F(x+k) has a constant solution for k for any x.

Numbers are the essence of the Universe

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**Stanley_Marsh****Member**- Registered: 2006-12-13
- Posts: 345

The first one, Let f(x)={x}={x+k} k must equally to any integers, the min period is 1

The second , let f(x)=cot(x+7)=cot(x+7+k) , since the period of cot is

then k=

*Last edited by Stanley_Marsh (2007-03-13 20:08:25)*

Numbers are the essence of the Universe

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**Stanley_Marsh****Member**- Registered: 2006-12-13
- Posts: 345

The third one ,

Numbers are the essence of the Universe

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**Stanley_Marsh****Member**- Registered: 2006-12-13
- Posts: 345

The fourth one ,

which is not below 0 , so the value of the function will always increase ,such function contains no period.Numbers are the essence of the Universe

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**Prakash Panneer****Member**- Registered: 2006-06-01
- Posts: 110

a) It is a fractional part. So, it is a periodic function.

b) Trigonometric function: It is also a periodic function.

c) Constant + or - Trig. function: Periodic function

d) Varibles +Trig : Non- periodic.

Letter, number, arts and science

of living kinds, both are the eyes.

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**gig****Member**- Registered: 2007-03-19
- Posts: 3

a piece of timber is cut in two lenghts in the ratio of 7:2. if the original piece of timber was 828 cm long,how long is the larger piece of the cut lenghts.

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**Maelwys****Member**- Registered: 2007-02-02
- Posts: 161

gig wrote:

a piece of timber is cut in two lenghts in the ratio of 7:2. if the original piece of timber was 828 cm long,how long is the larger piece of the cut lenghts.

To figure this out, you have to do a couple steps.

- First, since the ratio is 7:2, you add those together to determine how many total "units" the timber can be broken into.

- Then divide the length by the number of units, to find the length of each unit.

- Then, simply multiplying the length of each unit by the number of units length you want to calculate will tell you how long that piece is.

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**Stanley_Marsh****Member**- Registered: 2006-12-13
- Posts: 345

well , if a timber cut in 7:2 . you can think like this , 7 blocks of wood belong to A , 2 blocks of wood belong to B , then what is the total blocks of wood , the wood is cut in 7+2=9 blocks , then how long is each block , 828/9. Then how long is 7 blocks together (larger) , (828/9)*7.

Numbers are the essence of the Universe

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