16-03-09 Limits Conceptual.

I think there is a lot of confusion on limits due to a post on forum

let us do the following problems...

Find the following

\\1) \lim_{x\rightarrow 1} (x^{n}) \\ \\2) \lim_{x\rightarrow 1^+} (x^{n}) \\ \\3) \lim_{x\rightarrow 1^-} (x^{n}) \\ \\4) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1^-} (x^{n}) \\ \\5) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1^+} (x^{n}) \\ \\6) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1} (x^{n}) \\ \\7) \lim_{n\rightarrow \infty, x\rightarrow 1^+} (x^{n}) \\ \\8) \lim_{n\rightarrow \infty, x\rightarrow 1^-} (x^{n}) \\ \\9) \lim_{n\rightarrow \infty, x\rightarrow 1} (x^{n}) \\ \\10) \lim_{x\rightarrow 1^+}\lim_{n\rightarrow \infty} (x^{n}) \\ \\11) \lim_{x\rightarrow 1^-}\lim_{n\rightarrow \infty} (x^{n}) \\ \\12) \lim_{x\rightarrow 1}\lim_{n\rightarrow \infty} (x^{n}) \\

48 Answers

13
deepanshu001 agarwal ·

shudnt the ans for 8th 0 and not not defined

1
skygirl ·

yup deepansh u correct...

amrita
wats the diff between q. 5 and 7 ??
in ur limits//

nishantsah
ek case me there is one limit after another
ek me both limit together

amrita
??
1 min
o achha
samjhi
bad observation
:(

62
Lokesh Verma ·

deepanshu you are right..

11
Mani Pal Singh ·

SIR 1ST KA ANSWER IS 0[1] (IF N->∞)

3
msp ·

i have one dbt sir

if a qn is asked like limx→af(x)=?

is it necessary to check LHL=RHL.pls reply

1
vector ·

bhaiya now wat s the conclusion

62
Lokesh Verma ·

@sankara It is necessary..
@ manipal.. but n is only an integer..

11
Mani Pal Singh ·

5TH DOES NOT EXIST

4TH IS 0

6TH DOES NOT EXIST

11
Mani Pal Singh ·

IF N IS AN INTEGER THEN
THEN
3RD TENDS TO ZERO

3
msp ·

first =second = third =1n

62
Lokesh Verma ·

\\1) \lim_{x\rightarrow 1} (x^{n}) \\ \\2) \lim_{x\rightarrow 1^+} (x^{n}) \\ \\3) \lim_{x\rightarrow 1^-} (x^{n}) \\ \\4) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1^-} (x^{n}) \\ \\5) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1^+} (x^{n}) \\ \\6) \lim_{n\rightarrow \infty}\lim_{x\rightarrow 1} (x^{n}) \\ \\7) \lim_{n\rightarrow \infty, x\rightarrow 1^+} (x^{n}) \\ \\8) \lim_{n\rightarrow \infty, x\rightarrow 1^-} (x^{n}) \\ \\9) \lim_{n\rightarrow \infty, x\rightarrow 1} (x^{n}) \\ \\10) \lim_{x\rightarrow 1^+}\lim_{n\rightarrow \infty} (x^{n}) \\ \\11) \lim_{x\rightarrow 1^-}\lim_{n\rightarrow \infty} (x^{n}) \\ \\12) \lim_{x\rightarrow 1}\lim_{n\rightarrow \infty} (x^{n}) \\

Q1) 1
Explanation: n is a constant.. It does not change.. hence it is obvious

Q2) 1
Explanation: n is a constant.. It does not change.. hence it is obvious

Q3) 1
Explanation: n is a constant.. It does not change.. hence it is obvious
Take an example: n=3 then do the same limit!

Q4) 1
n is constant till x has converged to 1-.. so before we take the 2nd limit of n-> infinity, the llimit has already converged to 1! hence the answer is 1

Q5) 1
n is constant till x has converged to 1-.. so before we take the 2nd limit of n-> infinity, the llimit has already converged to 1! hence the answer is 1

Q6) 1
n is constant till x has converged to 1-.. so before we take the 2nd limit of n-> infinity, the llimit has already converged to 1! hence the answer is 1

Q7) Not Defined
Basically it is from the definiton of every subsequence! That is not in syllabus. basically we can have a case when x->1 first and then n->infinity .. then in that case we will have 1 as the limit. In other case when x goes to infinity slower than n then the limit could be infinite or even numbers other than 1!
example will be x(n) = (1+1/n)
the limit will be e!

Q8) Not Defined
same explanation as 7
Q9) Not Defined
same explanatino as 7
Q10) infinite
here x is >1 .. and then n goes to infinity first.. so the limit will be infinite (I should have mentioned that x>1)
Q11) zero.. take the same reasoning as 10

Q12) Not Defined
Not defined because we dont know if initially x >1 or <1 or =1
In each of the 3 cases, we will get different answers!

basically 7,8,9 are not insyllabus..
I was trying to show that they are different tihngs from 10,11,12 and 4,5,6
Dont worry if you dont understand them

11
Mani Pal Singh ·

SIR YA MEIN PAGAL HO GAYA HOON [17]
YA AAPKE ENSWERS WRONG HAIN[1]

1
vector ·

??

3
msp ·

can u pls explain 7th 8th 9th and wat is the difference 4th,5th,6th qns

13
deepanshu001 agarwal ·

ans for 7th shud b ∞

1
Philip Calvert ·

[12] yaha kuch samajh mein nahi aa raha hai....

e to power f(x)-1 into g(x) kahan lagta hai ???

1
°ღ•๓яυΠ·

1∞ mein

11
Mani Pal Singh ·

SIR I AGREE WITH ONLY

1
7
9
10
11
12

11
Mani Pal Singh ·

sir i am a dumb fool[17]
i thought my limits r good but u proved me wrong
so please kindly give the solutions to the suspected ones[1]

1
playpower94 ·

[12] .... [1] that sum came out to be LIMIT ROCKZ really handy coz certain new things was known [1]
thnks bhaiya [1]

11
Mani Pal Singh ·

sir ab aur intezaar nahin ho raha please tell the solutions also

106
Asish Mahapatra ·

this wud be my solutions..
(1) lim(x→1)xn = 1 as LHL = 1n = RHL
(2) this is just RHL of abv Q
(3) this is just LHL of abv Q
(4) this means lim(n→∞)[lim(x→1)xn] first we evaluate lim(x→1)xn then the answr for that is evaluated for n→∞

so, it is lim(n→∞) 1 = 1

(5) This is lim(n→∞) of Q2. = lim(n→∞) 1 = 1
(6) this is lim(n→∞) of Q3 = 1lim(n→∞) 1 = 1

(7)(8)(9) this means simultaneously, x→1 and n→∞.. so undefined

106
Asish Mahapatra ·

(10) it is basically lim(x→1+)x→∞ = infinity
(11) it is basically lim(x→1-)x→∞ = zero
(12) LHL ≠RHL hence limit is undefined.

62
Lokesh Verma ·

Read Post 36.

1
vector ·

@deepanshu it means u cnsidered tht same

1
vector ·

why 1 ds nt exist

13
deepanshu001 agarwal ·

for 1, 2 and 3. ans shud b 1

1
skygirl ·

2 and 3 both one...

1 wala bhi 1...

y dsnt exist ?

13
deepanshu001 agarwal ·

sry correctd myself while doing 1 i thot n tends to infinity

1
skygirl ·

take n=1, limx->1 x ...

from both sides it tends 1 ...

so 1... for q.no1.

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