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lim-x-0-4e-3x-9e-2x-6x-5-x-3-




Question Number 185539 by mathlove last updated on 23/Jan/23
lim_(x→0) ((4e^(3x) −9e^(2x) +6x+5)/x^3 )=?
$$\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}{e}^{\mathrm{3}{x}} −\mathrm{9}{e}^{\mathrm{2}{x}} +\mathrm{6}{x}+\mathrm{5}}{{x}^{\mathrm{3}} }=? \\ $$
Answered by Ar Brandon last updated on 23/Jan/23
L=lim_(x→0) ((4e^(3x) −9e^(2x) +6x+5)/x^3 )       =lim_(x→0) ((4(1+3x+((9x^2 )/2)+((27x^3 )/6))−9(1+2x+((4x^2 )/2)+((8x^3 )/6))+6x+5)/x^3 )       =lim_(x→0) ((18x^3 −12x^3 )/x^3 )=6
$$\mathscr{L}=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}{e}^{\mathrm{3}{x}} −\mathrm{9}{e}^{\mathrm{2}{x}} +\mathrm{6}{x}+\mathrm{5}}{{x}^{\mathrm{3}} } \\ $$$$\:\:\:\:\:=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}\left(\mathrm{1}+\mathrm{3}{x}+\frac{\mathrm{9}{x}^{\mathrm{2}} }{\mathrm{2}}+\frac{\mathrm{27}{x}^{\mathrm{3}} }{\mathrm{6}}\right)−\mathrm{9}\left(\mathrm{1}+\mathrm{2}{x}+\frac{\mathrm{4}{x}^{\mathrm{2}} }{\mathrm{2}}+\frac{\mathrm{8}{x}^{\mathrm{3}} }{\mathrm{6}}\right)+\mathrm{6}{x}+\mathrm{5}}{{x}^{\mathrm{3}} } \\ $$$$\:\:\:\:\:=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{18}{x}^{\mathrm{3}} −\mathrm{12}{x}^{\mathrm{3}} }{{x}^{\mathrm{3}} }=\mathrm{6} \\ $$
Commented by mathlove last updated on 23/Jan/23
thanks
$${thanks} \\ $$

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