x趋于0时 12+12x^2×sin1x-6xcos1x-sin1xx的极限
首先观察到,在分子中,当x趋于0时,sin(1/x)和cos(1/x)都会发散。因此,我们需要先处理这两个函数。
由于-1≤sin(θ)≤1和-1≤cos(θ)≤1,我们可以得到以下不等式: -1 ≤ sin(1/x) ≤ 1 -1 ≤ cos(1/x) ≤ 1
接下来,我们来看待含有sin(1/x)和cos(1/x)的项。我们可以将它们展开为泰勒级数,以便我们可以对其进行处理。
sin(1/x) = (1/x) - (1/3!x^3) + (1/5!x^5) - ... cos(1/x) = 1 - (1/2!x^2) + (1/4!x^4) - ...
现在,我们可以将sin(1/x)和cos(1/x)代入原式,并进行化简:
(1/2 + 12x^2×sin(1/x) - 6xcos(1/x) - sin(1/x))/x = (1/2 + 12x^2((1/x) - (1/3!x^3) + (1/5!x^5) - ...) - 6x(1 - (1/2!x^2) + (1/4!x^4) - ...) - ((1/x) - (1/3!x^3) + (1/5!x^5) - ...))/x = (1/2 + 12(1 - (1/3!x^2) + (1/5!x^4) - ...) - 6x(1 - (1/2!x^2) + (1/4!x^4) - ...) - (1/x) + (1/3!x^3) - (1/5!x^5) + ...)/x = (1/2 + 12 - 12(1/3!x^2) + 12(1/5!x^4) - ... - 6x + 6(1/2!x^2) - 6(1/4!x^4) + ... - (1/x) + (1/3!x^3) - (1/5!x^5) + ...)/x = (25/2 + (-12/3! + 6/2!)x^2 + (12/5! - 6/4!)x^4 + ...)/x
现在,我们可以考虑当x趋近于0时,各项的极限情况。 当x→0时,(25/2)/x → ∞ 当x→0时,(-12/3! + 6/2!)x^2 → 0 当x→0时,(12/5! - 6/4!)x^4 → 0 ...
因此,我们可以得到最终的极限: lim(x→0) [(1/2 + 12x^2×sin(1/x) - 6xcos(1/x) - sin(1/x))/x] =
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