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lim-x-2-4-2-x-x-2-




Question Number 221348 by RoseAli last updated on 31/May/25
lim_(x→2)  ((4−2^x )/(x−2))
$$\underset{{x}\rightarrow\mathrm{2}} {\mathrm{lim}}\:\frac{\mathrm{4}−\mathrm{2}^{{x}} }{{x}−\mathrm{2}} \\ $$
Answered by mr W last updated on 31/May/25
=lim_(x→0) ((4(1−2^x ))/x)  =lim_(x→0) ((4(1−e^(xln 2) ))/x)  =lim_(x→0) ((4(1−1−xln 2−((x^2 ln^2  2)/(2!))−...))/x)  =−4 ln 2
$$=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}\left(\mathrm{1}−\mathrm{2}^{{x}} \right)}{{x}} \\ $$$$=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}\left(\mathrm{1}−{e}^{{x}\mathrm{ln}\:\mathrm{2}} \right)}{{x}} \\ $$$$=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\frac{\mathrm{4}\left(\mathrm{1}−\mathrm{1}−{x}\mathrm{ln}\:\mathrm{2}−\frac{{x}^{\mathrm{2}} \mathrm{ln}^{\mathrm{2}} \:\mathrm{2}}{\mathrm{2}!}−…\right)}{{x}} \\ $$$$=−\mathrm{4}\:\mathrm{ln}\:\mathrm{2} \\ $$
Answered by mnjuly1970 last updated on 02/Jun/25
   =^(hopital) lim_(x→2) ((−2^x ln(2))/1)=−4ln(2)
$$\:\:\:\overset{{hopital}} {=}{lim}_{{x}\rightarrow\mathrm{2}} \frac{−\mathrm{2}^{{x}} {ln}\left(\mathrm{2}\right)}{\mathrm{1}}=−\mathrm{4}{ln}\left(\mathrm{2}\right) \\ $$

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