Math, asked by tokaians, 1 year ago

Limit x tends to 0 1-√cos x/ x^2 evaluate the limit

Answers

Answered by Ayusha765
26
the answer is 1/4
refer to the image attached for solution
Attachments:

tokaians: why did you divide and multiply x^2 with 4
Ayusha765: lim(sinx/x) as x-->0 is 1 so in the numerator there we have sin^2(x/2); for each sin(x/2) we divide by x/2 and for sin^2(x/2) we divide by x^2/4;since we only have x^2 in the denominator so to bring (x^2/4) i have multiplied and divided by 4
Ayusha765: if still problem persists then pls inform
Anonymous: :)
tokaians: so when we have x/2 we divide an multiply with x/2 and when we have sin^2 x/2 we divide and multiply with x^2/4
Ayusha765: we ultimately bring in the form sin(A)/A as A tends to 0
Ayusha765: so we multiply and divide accordingly
Ayusha765: we also have the L hospitals rule...but do not go for it.....use it only when all other methods fail
Anonymous: yes you r right ✌ it is decreases your thinking capability
Anonymous: i gave it coz you have answered in the other way
Answered by Anonymous
8
the another method to solve o/o form is l-hospital rule 

lim x→o   1-√cosx / x²
applying l hospital rule 

limx→0        d/dx(1- √cosx) / d/dx(x²) 
lim x→0        sinx/2√cosx / 2x 
=> lim x→0    sinx/4x√cosx
 we know that lim x→0 sinx/x = 1 and lim x→0 cos x = 1 
apply it here we get 

lim x→0     1/4 

ask we if you will face any problem regarding this 


          

Anonymous: we differentiate numerator and denominator separately
Anonymous: until zero by zero form is disappeared
tokaians: ok
Anonymous: ye understand ?
tokaians: yes
tokaians: so what is the differentiation of 1-√cosx
Anonymous: 0 - 1/2(-sinx)/root cosx
Anonymous: chain rule
tokaians: okkk
Anonymous: :) ask me if you will face any in this chapter
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