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Question Number 78897 by Mikael_786 last updated on 21/Jan/20

Commented by mind is power last updated on 21/Jan/20

translate please

translateplease

Commented by mr W last updated on 21/Jan/20

what is option D?

whatisoptionD?

Commented by Mikael_786 last updated on 21/Jan/20

help plz

helpplz

Commented by john santu last updated on 21/Jan/20

lim_(x→0) [g(x^2 )×2x]×(1/x^3 )=1  lim_(x→0) ((2g(x^2 ))/x^2 )=1 ⇒lim_(x→0) ((2xg′(x^2 ))/(2x))=1  g′(0)=1.  now we work lim_(x→0) ((g′(x^2 )−5x)/(x−3))=  ((g′(0)−5×0)/(0−3))=−(1/3)

limx0[g(x2)×2x]×1x3=1limx02g(x2)x2=1limx02xg(x2)2x=1g(0)=1.nowweworklimx0g(x2)5xx3=g(0)5×003=13

Commented by john santu last updated on 21/Jan/20

not clear option D and E

notclearoptionDandE

Commented by Mikael_786 last updated on 21/Jan/20

thank you Sir

thankyouSir

Commented by mr W last updated on 21/Jan/20

what if e.g.  g(x)=(x/2)(1+2x+3x^2 )  which fulfills the condition but  g′(0)≠1.  or g(x)=((x cos x)/2) which also fulfills  the condition.

whatife.g.g(x)=x2(1+2x+3x2)whichfulfillstheconditionbutg(0)1.org(x)=xcosx2whichalsofulfillsthecondition.

Commented by mr W last updated on 21/Jan/20

Mikael sir:  please translate the question and  tell the option D, or E if exists!

Mikaelsir:pleasetranslatethequestionandtelltheoptionD,orEifexists!

Commented by Mikael_786 last updated on 21/Jan/20

Commented by Mikael_786 last updated on 21/Jan/20

D option exists, but I don′t know too.

Doptionexists,butIdontknowtoo.

Commented by mr W last updated on 21/Jan/20

i think the answer could be −(1/6).

ithinktheanswercouldbe16.

Answered by mr W last updated on 21/Jan/20

((d∫_0 ^x^2  g(t)dt)/dx)=2xg(x^2 )  lim_(x→0) ((2xg(x^2 ))/x^3 )=1  lim_(x→0) ((g(x^2 ))/x^2 )=(1/2)  ⇒g(x^2 )=((x^2 h(x))/2) with lim_(x→0) h(x)=1  ⇒g(x)=((xh((√x)))/2)  ⇒g′(x)=((h((√x)))/2)+(((√x)h′((√x)))/4)  ⇒g′(x^2 )=((h(x))/2)+((xh′(x))/4)  lim_(x→0) g′(x^2 )=lim_(x→0) ((h(x))/2)+0=(1/2)  lim_(x→0) ((g′(x^2 )−5x)/(x−3))=(((1/2)−0)/(0−3))=−(1/6)

d0x2g(t)dtdx=2xg(x2)limx02xg(x2)x3=1limx0g(x2)x2=12g(x2)=x2h(x)2withlimx0h(x)=1g(x)=xh(x)2g(x)=h(x)2+xh(x)4g(x2)=h(x)2+xh(x)4limx0g(x2)=limx0h(x)2+0=12limx0g(x2)5xx3=12003=16

Commented by john santu last updated on 21/Jan/20

((d(g(x^2 )))/dx)= 2x g′(x^2 ) sir   why ((h(x))/2)+((xh′(x))/4)?

d(g(x2))dx=2xg(x2)sirwhyh(x)2+xh(x)4?

Commented by mr W last updated on 22/Jan/20

by using the form y′ you should be  very careful what you really mean,  i.e. with respect to what?  assume g(x)=x^2 (1+x). can you tell me  what g′(x^2 ) is concretely in your eqn.  ((d(g(x^2 )))/dx)= 2x g′(x^2 )=?

byusingtheformyyoushouldbeverycarefulwhatyoureallymean,i.e.withrespecttowhat?assumeg(x)=x2(1+x).canyoutellmewhatg(x2)isconcretelyinyoureqn.d(g(x2))dx=2xg(x2)=?

Commented by john santu last updated on 22/Jan/20

chain rule sir  let u= x^2  ⇒(du/dx) = 2x  now ((d(g(x^2 )))/dx)= ((d(g(u)))/dx)  =((d(g(u)))/du)×(du/dx)= g′(u)×2x  that right?

chainrulesirletu=x2dudx=2xnowd(g(x2))dx=d(g(u))dx=d(g(u))du×dudx=g(u)×2xthatright?

Commented by mr W last updated on 22/Jan/20

yes!

yes!

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