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lim-x-0-sin-x-tan-x-x-3-a-1-2-b-1-4-c-1-2-d-1-4-




Question Number 190300 by mnjuly1970 last updated on 31/Mar/23
     lim_( x→0) (( sin(x) −tan(x))/x^( 3) )       a:    (1/2)           b:    ((−1)/4)         c:     ((−1)/2)          d:    ((−1)/4)
$$ \\ $$$$\:\:\:\mathrm{lim}_{\:{x}\rightarrow\mathrm{0}} \frac{\:{sin}\left({x}\right)\:−{tan}\left({x}\right)}{{x}^{\:\mathrm{3}} } \\ $$$$\:\:\:\:\:{a}:\:\:\:\:\frac{\mathrm{1}}{\mathrm{2}}\:\:\:\:\:\:\:\:\:\:\:{b}:\:\:\:\:\frac{−\mathrm{1}}{\mathrm{4}}\:\:\:\:\:\:\:\:\:{c}:\:\:\:\:\:\frac{−\mathrm{1}}{\mathrm{2}}\:\:\:\:\:\:\:\:\:\:{d}:\:\:\:\:\frac{−\mathrm{1}}{\mathrm{4}} \\ $$$$ \\ $$
Answered by som(math1967) last updated on 31/Mar/23
lim_(x→0)  ((sinx(cosx−1))/(x.x^2 cosx))  lim_(x→0) ((sinx)/x)×lim_(x→0) ((−2sin^2 (x/2))/(x^2 cosx))  lim_(x→0) ((−sin^2 (x/2))/(2×((x/2))^2 ))×(1/(cosx))  =−(1/2)   (c)
$$\underset{{x}\rightarrow\mathrm{0}} {{lim}}\:\frac{{sinx}\left({cosx}−\mathrm{1}\right)}{{x}.{x}^{\mathrm{2}} {cosx}} \\ $$$$\underset{{x}\rightarrow\mathrm{0}} {{lim}}\frac{{sinx}}{{x}}×\underset{{x}\rightarrow\mathrm{0}} {{lim}}\frac{−\mathrm{2}{sin}^{\mathrm{2}} \frac{{x}}{\mathrm{2}}}{{x}^{\mathrm{2}} {cosx}} \\ $$$$\underset{{x}\rightarrow\mathrm{0}} {{lim}}\frac{−{sin}^{\mathrm{2}} \frac{{x}}{\mathrm{2}}}{\mathrm{2}×\left(\frac{{x}}{\mathrm{2}}\right)^{\mathrm{2}} }×\frac{\mathrm{1}}{{cosx}} \\ $$$$=−\frac{\mathrm{1}}{\mathrm{2}}\:\:\:\left({c}\right) \\ $$
Commented by mnjuly1970 last updated on 31/Mar/23
very nice sir ..
$${very}\:{nice}\:{sir}\:.. \\ $$
Answered by cortano12 last updated on 31/Mar/23
  L=lim_(x→0)  ((sin (x)−tan (x))/x^3 )     L=lim_(x→0)  ((tan x(cos x−1))/x^3 )    L= lim_(x→0)  ((−sin^2 x)/(x^2 (cos x+1)))=−(1/2)
$$\:\:\mathrm{L}=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\:\frac{\mathrm{sin}\:\left(\mathrm{x}\right)−\mathrm{tan}\:\left(\mathrm{x}\right)}{\mathrm{x}^{\mathrm{3}} }\: \\ $$$$\:\:\mathrm{L}=\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\:\frac{\mathrm{tan}\:\mathrm{x}\left(\mathrm{cos}\:\mathrm{x}−\mathrm{1}\right)}{\mathrm{x}^{\mathrm{3}} } \\ $$$$\:\:\mathrm{L}=\:\underset{{x}\rightarrow\mathrm{0}} {\mathrm{lim}}\:\frac{−\mathrm{sin}\:^{\mathrm{2}} \mathrm{x}}{\mathrm{x}^{\mathrm{2}} \left(\mathrm{cos}\:\mathrm{x}+\mathrm{1}\right)}=−\frac{\mathrm{1}}{\mathrm{2}} \\ $$
Commented by mnjuly1970 last updated on 31/Mar/23
 thx alot  sir  cortano
$$\:{thx}\:{alot}\:\:{sir}\:\:{cortano} \\ $$

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