## anonymous one year ago can someone help me please?:)

1. anonymous

2. xapproachesinfinity

1 step is okay yes we can square root both sides no problem right?

3. anonymous

sure

4. xapproachesinfinity

oh that's second step not first

5. xapproachesinfinity

first is just equation itself

6. anonymous

yea

7. xapproachesinfinity

so 1 and 2 no problem

8. hba

Do you think there is a fault in the 3rd step?

9. xapproachesinfinity

3 now what do you think

10. xapproachesinfinity

look at one side of the equation at a time

11. anonymous

sorry, my laptop is lagging,and it step 3 looks fine to me:S

12. xapproachesinfinity

hehe can we do this $$\sqrt{a^2+b^2}=a+b?$$

13. anonymous

i guess not lol

14. hba

Well as @xapproachesinfinity said the R.H.S is fine as $\sqrt{c^2} = c$ as they cancel

15. xapproachesinfinity

yes it is not allowed

16. anonymous

rhs?

17. hba

But it should be something like $\sqrt{(a+b)^2}$ to become a+b

18. xapproachesinfinity

right hand side :)

19. hba

So to get that we know that we want something like $\sqrt{a^2+2ab+b^2}$

20. xapproachesinfinity

for this $$\sqrt{b^2+a^2}$$ we cannot do anything to it

21. hba

We cannot? :o

22. xapproachesinfinity

yes we can't as far as the problem is concerned!

23. hba

We can solve it by adding root(2ab) on both sides?

24. anonymous

im confused lol

25. xapproachesinfinity

hmm you meant $$|c|+\sqrt{2ab}=\sqrt{a^2+b^2}+\sqrt{2ab }$$

26. xapproachesinfinity

is that what you saying ?

27. hba

No that won't do but we can add something to it so it becomes root(a^2+b^2+2ab)

28. xapproachesinfinity

you can't you add 2ab under the root so you must subtract it under the root

29. hba

Well we shouldn't had done this step in the first place lol :p

30. xapproachesinfinity

this problem we need to go back to a^2+b^2=c^2 solve a a^2=c^2-b^2 take root root(a^2)=root(c^2-b^2) |a|=root(c^2-b^2) a=+-root(c^2-b^2) the correct approach

31. hba

We could have done something like a^2 = c^2 - b^2 so we'd get a= root(c^2-b^2) for an answer

32. hba

Lol we just wrote the samething

33. xapproachesinfinity

yeah true

34. xapproachesinfinity

but we need +- too

35. anonymous

:S

36. hba

Agreed

37. hba

But the ques says +

38. xapproachesinfinity

eh i didn;t read that positive reals part lol

39. xapproachesinfinity

so it has to be a=root(c^2-b^2)

40. anonymous

yall are arguing a question which you both know but are not helping the actual person who needs help, both of u just completly confused me

41. hba

@Sammii09 LoL

42. xapproachesinfinity

ok now we need to promptly do this problem first step checked second step no we need to solve for a^2 third step square rroot both sides 4th step a=... that is it

43. hba

I'm just gonna leave @xapproachesinfinity is here

44. xapproachesinfinity

haha lol @Sammii09

45. xapproachesinfinity

look at my comment before this i did the problem

46. anonymous

ok

47. xapproachesinfinity

first step is okay 2 step no ( we need to isolate a^2 in one side) 3 step (no that's not allowed) (suggest take square root of both side of this equation a^2=c^2-b^2) 4 step no (since third is wrong 4 will also be wrong) (suggested a=root(c^2-b^2)) done!

48. anonymous

okay thanks

49. xapproachesinfinity

no problem