Ask your own question, for FREE!
Mathematics 20 Online
OpenStudy (christos):

Calculus, Can you please help me solve (a) and (b) ? https://www.dropbox.com/s/xslzq5tpy26zpkd/Screenshot%202013-11-02%2021.04.51.jpg

OpenStudy (christos):

@hartnn

OpenStudy (christos):

@AravindG

hartnn (hartnn):

so did you apply l.h rule ?

OpenStudy (christos):

I did

OpenStudy (christos):

And I got tanxcosx/sinxsec^2x

hartnn (hartnn):

yes, now simplify that

hartnn (hartnn):

tan cos is just sin

OpenStudy (christos):

oh so its 1

hartnn (hartnn):

yep

OpenStudy (christos):

how about (b) ?

OpenStudy (christos):

what would your first step be ?

OpenStudy (christos):

as far as I understand is something ^inf form

hartnn (hartnn):

taking log on both sides

OpenStudy (anonymous):

what the i.h rule

hartnn (hartnn):

L = lim .... log L = lim log ...

OpenStudy (jusaquikie):

it's L.H. and he means L'hospital's

hartnn (hartnn):

^

OpenStudy (christos):

I got ln(y) = ln(1 + 2/x) / (1/x)

OpenStudy (jusaquikie):

b is easy just put in infinity or a large number like 1,000,000 and see what it is close too

hartnn (hartnn):

yes, you can differentiate now...0/0 gorm

hartnn (hartnn):

form

OpenStudy (christos):

is that 1 too ?

OpenStudy (jusaquikie):

yes

OpenStudy (christos):

but wait

OpenStudy (christos):

I still have an ln(y) here

OpenStudy (jusaquikie):

1+0 to any power is still just 1

hartnn (hartnn):

you got 1 ??? or 2 ?

OpenStudy (christos):

1 :(

hartnn (hartnn):

you should get 2

OpenStudy (christos):

oh I messed up badly hold

hartnn (hartnn):

num diff = -2/x^2

OpenStudy (christos):

true, its 2

hartnn (hartnn):

so , ln y = 2

hartnn (hartnn):

y= ... ?

OpenStudy (christos):

e^2 !

hartnn (hartnn):

yaaay

OpenStudy (christos):

;p

OpenStudy (christos):

lemme try © too just to be safe

hartnn (hartnn):

sure :)

OpenStudy (christos):

inf/0 is not eligible for LH right ?

hartnn (hartnn):

how r u getting inf for numerator ?

OpenStudy (christos):

I did it like this - 1/six(x) / x

OpenStudy (christos):

nah its stupid, hold on , lol

hartnn (hartnn):

let me make your life easier 1/x - cosec x = (1-x cosec x )/x

OpenStudy (christos):

oh so thats inf

hartnn (hartnn):

wot ?

hartnn (hartnn):

treat 0*inf as 0

OpenStudy (christos):

x cosec x this is 0

OpenStudy (christos):

so we have 1/x

OpenStudy (christos):

aka inf ?

hartnn (hartnn):

num = 0 denom = 0 0/0 apply L.H .-.

OpenStudy (christos):

man, (1-x cosec x )/x <------ xcsc(x) is 0 right ?

hartnn (hartnn):

yes

OpenStudy (christos):

so we are left with 1/x right ?

OpenStudy (christos):

nvm, I got it

hartnn (hartnn):

i was asking for the form

hartnn (hartnn):

whether you can apply LH or not

OpenStudy (christos):

actually I didn't got it

OpenStudy (christos):

ah

OpenStudy (christos):

I don't think we need to apply it ?

hartnn (hartnn):

is there 0/0 form ?

OpenStudy (christos):

there is (1 + 0 / 0 ) form

OpenStudy (christos):

ah if I break it there is 0/0

OpenStudy (christos):

that's what you mean ?

hartnn (hartnn):

i am stupid , sorry do it this way only 1/x - 1/sin x = (sin x - x) / (x sin x)

OpenStudy (christos):

oh hm

OpenStudy (christos):

the result is 0 ?

hartnn (hartnn):

yes!

OpenStudy (christos):

:D thanks a lot

hartnn (hartnn):

welcome ^_^

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!