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Lt (tanx/x)^(1/ x^2) as x nears zero?

I was just trying to deduce the limit of (tanx/x)^(1/ x^2)as x goes to zero, I wrote tanx as sinx/cosx and then expanded sinx and cosx in terms of x respectively, but after expansion I was not able to move ahead with this problem.Can anyone here help me in this case?I want you guys to give the answer by expanding cos x and sin x in terms of x.

Update:

without lhopital rule i want u guys to gimme the answer.

5 Answers

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  • 1 decade ago
    Favorite Answer

    You come till the last step as above,i.e,

    Let L=Lim (tanx/x)^(1/x^2)

    Than,

    Ln L=Lim (1/x^2)Ln(tanx/x) (Ln for natural log, i.e.log to base e)

    Now, as x->0, the numerator, Ln(tanx/x) goes to zero faster than the denominator, x^2(This is arrived at by showing that by expanding tan into ratio of sine and cosine series, tanx/x goes to one ans x goes to zero, linearly, i.e. at the same pace as x). Hence the limit goes to zero(This is an indirect use of L'Hospital's rule, by saying goes to zero faster, I mean differential is greater).

    Thus,

    Ln L=0 => L=1(answer)

  • Anonymous
    1 decade ago

    see the problem in this question is that here the power is in the form of variable(which includes 'x'), and the procedure to solve these types of question is as follows

    1. First let the question equals to 'y' (or any other variable as u wish).

    2. "TAKE THE LOGaritm OF BOTH SIDES".

    3. after that u know the property log a^x =x log a.

    after folowilg this ur quetion will convert to

    log y = lim 1/x^2[log(tanx/x)]

    now as the limit x ---> 0 according to the question then the L hospital's rule is applicable on that

    and solve the further question intil the difrential comes a determined value...

    At the desk of: Abishek verma...

  • ?
    Lv 4
    4 years ago

    set x^3 -x² - 2x to 0 you may factor an x out x(x² - x - 2) factor out what's in parenthesis x(x - 2)(x + a million) set each and every x to 0 x=0 x - 2 = 0 so x = 2 x + a million = 0 so x = -a million

  • Anonymous
    1 decade ago

    ƒ=Lt (tanx/x)^(1/ x²)[say]

    Then, logƒ=Lt (1/x²)log(tanx/x)

    =>logƒ=Lt [log(tanx)-log(x)]/x²

    =>Use L.Hopital Rule Next.

    Taking log is not a pre-defined property of the limit, but it has to be taken in this case.

  • Anonymous
    1 decade ago

    Its one of the deepest mysteries of maths.

    work work till you succeed.

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