## kittycat01 2 years ago tan^-1[(√x+√a)/(1-√(xa))] differentiate it plz m gtting 1/2(√x) which is not correct answer is 1/[2(√x)(1+x)]

1. hartnn

same type of question with different substitution

2. kittycat01

hmm i think i did something wrong let me do it again

3. kittycat01

well u don't have to substitue :) @hartnn i think i forgot to differentiate tan^-1 (x)^1/2 i missed the tan^-1 part

4. hartnn

say, sqrt x= tan y sqrt a = tan alpha then , [(√x+√a)/(1-√(xa))] =... ?

5. hartnn

ohh..so now did u get it ?

6. kittycat01

u have to use tan^-1 x + tan^-1 y formula well not now

7. kittycat01

trying again

8. kittycat01

:'( not getting :'(

9. kittycat01

how to differnatiate tan^-1(x)^1/2

10. hartnn

use chain rule, know about it ?

11. kittycat01

no :'( that's the problem simple chain rule i know

12. kittycat01

like this one sin(cos3x) but never did for inverse trign.........

13. kittycat01

is the differenatition of tan^-1(x)^1/2 is

14. kittycat01

is =X =1/(1+(x^1/2)^2 . 1/2*(x)^-1/2 ????????

15. hartnn

ok, derivative of tan^{-1} x is 1/(1+x^2), right ?? for derivative of tan^{-1} sqrt(x) you do 1/(1+ [\sqrt x]^2) times deribative of sqrt x

16. kittycat01

yep

17. kittycat01

i think i have used chain rule -_- is that a chain rule @hartnn

18. souvik

you did it,,,kitty

19. hartnn

didn't you get the answer then ? yes, thats was chain rule only...

20. kittycat01

lol i know everything but still do silly things -_- @souvik

21. souvik

it happens some time...

22. kittycat01

@hartnn - chain rule :O so that's a chain rule

23. hartnn

24. kittycat01

not some times everytime it happens

25. souvik

26. kittycat01

bcoz of calculation mistake i lost 3 marks in maths prob :'( i did everything correct but in final answer i made a error in multiplication

27. kittycat01

MSD??????

28. kittycat01

@hartnn -tahnx :)

29. hartnn

hey, welcome anytime ^_^

30. kittycat01

:)

31. souvik

Indian cricket team captain...

32. kittycat01

oh :OOO ms dhoni :OOO i don't like him lol

33. souvik

why?

34. kittycat01

reminds me of my frenemy :P