## A community for students. Sign up today

Here's the question you clicked on:

## anonymous one year ago need help on fourier transform immediately

• This Question is Open
1. anonymous

2. anonymous

@ganeshie8

3. anonymous

question 1 ab c and question 3 a b c

4. anonymous

@pooja195 kindly

5. anonymous

@IrishBoy123 kindly

6. IrishBoy123

for first one, look here http://openstudy.com/users/irishboy123#/updates/55e4c101e4b0445dfd12b32e you just need to tweak this ie ad $$e^{-a}$$ in as a constant

7. IrishBoy123

you should get $\frac{2a}{a^2 + w^2}$

8. anonymous

i did the first one though, sorry, i need the rest

9. IrishBoy123

for the next one you do $\frac{1}{\sqrt{2\pi}} \left[ \int_{-\infty}^{0} -x e^{-i \omega \ x} dx + \int_{0}^{1} x e^{-i \omega \ x} dx + 0 \right]$

10. IrishBoy123

caveat, i am pretty rusty on these but i'd knock this out as integration by parts

11. anonymous

thank you

12. anonymous

i need step by step though pretty urgent

13. anonymous

kindly

14. IrishBoy123

if you cannot integrate by parts i think you are going to be in trouble especially if you are in a rush use $$u' = \pm x , \ v = e^{-i \omega \ x}$$

15. IrishBoy123

for (c) you have this |dw:1441264946681:dw| but double check your notation that's trivial, i'd guess

16. IrishBoy123

for 3 you'd need to be familiar with known transforms this kind of thing: http://uspas.fnal.gov/materials/11ODU/FourierTransformPairs.pdf i could read through them but if you are in a rush i would be wasting your time.... :-(

17. anonymous

thanl you so much

18. IrishBoy123

if i read the h notation correctly, (c) simplifies to $2\int_{0}^{1} \ sin x \ dx$

19. IrishBoy123

soz make that simplification $\frac{-i}{\sqrt{2 \pi}} . 2\int_{0}^{1} \ sin \ \omega x \ dx$

20. anonymous

Just out of curiosity, what definition does your text use for the transform?

21. IrishBoy123

ah! kept meaning to bring that up the table i linked uses https://gyazo.com/e52ab73f1c94060a3355f9d06b0890af as opposed to https://gyazo.com/fa16fc59e58bc8dcc5084074a5240abf ie the $$1/\sqrt{2 \pi }$$ flavour wolfram uses the latter also as i have checked 3a,b,c there

22. IrishBoy123

here are some scribbles. in order they occur 3(a) 3(c) 3(a) done a slightly different way 3(c) not finished issues, 1/ there may be a $$2 \pi$$ or $$\sqrt{2 \pi}$$ missing depending on where it sat in the definition used for the transform. 2/ i have a sign problem with 3(a), very annoying as it cropped up both times i scribbled it out. i get minus what wolfram gets each time... 3/ i can't make sense of where the delat fits in in 3(c) . it is a lot easier just doing the integral but using the tables, haven't done that in a long time..... this might be of some help.

23. anonymous

thanks a ton

24. IrishBoy123

be careful with it, i haven't done this is ages. but if you are stuck, it still might help. good luck :p

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy