## maheshmeghwal9 3 years ago Plz help:)

1. dpaInc

hey mahesh

2. maheshmeghwal9

3. maheshmeghwal9

why b>1? Why not b>0?

4. maheshmeghwal9

in the attachment.

5. dpaInc

holymoly that's one big pic.

6. maheshmeghwal9

should I make it small?

7. dpaInc

sawrite....

8. maheshmeghwal9

9. dpaInc

b>1 because the negatitve exponents will take care of values for b between 0 and 1... that make sense?

10. dpaInc

so it is defined for b>1

11. maheshmeghwal9

didn't understand ya main concept:(

12. dpaInc

let's do this then...

13. dpaInc

|dw:1337931693406:dw|

14. dpaInc

do you see why b doesn't have to be defined between 0 and 1?

15. maheshmeghwal9

but what is the problem for 0<b<1.Isn't it defined for exponential f(x) too. Since it also gives a value which is defined as "x". in ur example|dw:1337932045573:dw| All r defined:)

16. dpaInc

there's no problem... with 0<b<1.. it's just not needed...

17. maheshmeghwal9

k! did it have no need due to log?

18. dpaInc

notice the base of logs CAN have a base between 0 and 1 also but could be transformed and written with a base bigger than 1

19. princeofwetlot

is there a reason why this was bumped?

20. maheshmeghwal9

Hi @experimentX I couldn't understand the my basic questiom.Plz help:)

21. experimentX

I don't understand the reason why b should be greater than 1, but b should always be greater than zero ... for that expression to be defined

22. maheshmeghwal9

ya I also think this:)

23. experimentX

$\log_b x = \frac{\log_k x}{\log_k b}$ Also between 0-1 $$\log_k b < 1$$

24. maheshmeghwal9

ok!

25. maheshmeghwal9

I had this problem while studying Logarithmic Differentiation. I think there is some connection between b>1 & Logarithmic Differentiation.

26. experimentX

$\frac{d}{dx} (\log_b x) = \frac{1}{x \ln b}$ At b=1, $$\ln b =0$$ is zero ... so it is undefined, so is the above expression, but for (0,1) the expression is defined http://www.wolframalpha.com/input/?i=plot+y+%3D+d%2Fdx+log [0.5%2C+x]+from+0+to+10 http://www.wolframalpha.com/input/?i=plot+y+%3D+log [0.5%2C+x]+from+0+to+10

27. maheshmeghwal9

So indirectly do u want to say that b>1 is right there! Please tell:)

28. experimentX

No ... i think i got it wrong it somewhere check this out http://www.wolframalpha.com/input/?i=plot+y+%3D+log [x%2C+2]+from+0+to+10

29. maheshmeghwal9

k! thanx alot:)

30. experimentX

wait ...

31. maheshmeghwal9

k!

32. experimentX

it seems i was right ... but somewhat not accurate http://www.wolframalpha.com/input/?i=plot+y+%3D+log [x%2C+5]+from+0+to+2

33. maheshmeghwal9

K! I understood that.I also think u r right.

34. experimentX

at b=0, $$\log_b x$$ is zero ... and $$dy/dx$$ is indeterminate

35. maheshmeghwal9

ok! thanx.

36. maheshmeghwal9

ow I have some clues. I will think on that point more. Thanx for clues:)

37. maheshmeghwal9

ow=now

38. experimentX

http://www.wolframalpha.com/input/?i=plot+y+%3D+d%2Fdx%28log [b%2C+x]%29+from+b%3D0+to+2 check this out

39. maheshmeghwal9

Hmm! I checked that:)

40. experimentX

b cannot be 1 and less than zero ... that's all

41. maheshmeghwal9

k! but can be (0,1)

42. experimentX

i guessed so ...

43. maheshmeghwal9

so we again came there; where was our doubt:)

44. maheshmeghwal9

this is a very confusing state; isn't it?

45. experimentX

well yes!!

46. maheshmeghwal9

What should we do now? by the way I have asked this to my sir also online, but they will receive question & give answer after almost a week!!!

47. experimentX

what was the original question??

48. maheshmeghwal9

Pardon me what do u want?; that is a video cutted part. I had this problem while studying video:)

49. experimentX

Oh ... i thought this is a part of the problem where you got stuck!!

50. maheshmeghwal9

so is there anyone in OS who can solve our problem:)

51. experimentX

I don't know ...

52. maheshmeghwal9

k! np:) Thanx for ur co-operation. When my problem is solved, i'll tell u too.

53. experimentX

k

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