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rainbow22
Group Title
lim x>0 [(3sin4x)/(sin 3x)] = 4 lim x>0 [(sin 4x/4x)x(3x/sin3x)]
How is this true?
 2 years ago
 2 years ago
rainbow22 Group Title
lim x>0 [(3sin4x)/(sin 3x)] = 4 lim x>0 [(sin 4x/4x)x(3x/sin3x)] How is this true?
 2 years ago
 2 years ago

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hartnn Group TitleBest ResponseYou've already chosen the best response.2
to get 4x in the denominator, 4x is multiplied in numerator and denominator. got some idea?
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.1
Multiply the whole thing by (12x/12x). rearrange.
 2 years ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.0
you can also use L'Hopitals Rule Take derivative of both top and bottom, then reevaluate the limit
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
But it would be undefined if I took the limit of the bottom
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.1
Always with l'Hopital's. You'd think it was the only thing anyone ever retained from calc. class.
 2 years ago

dumbcow Group TitleBest ResponseYou've already chosen the best response.0
haha..yeah pretty much
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
I haven't learned it yet :(
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.1
They're learning about sinc(x) here anyway ... that's a few lectures before the class on l'Hopital's.
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.2
dw:1347162711646:dw got it now?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.2
just use sin t / t when limit t>0 = 1 formula.
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.1
@hartnn what did you multiply by? It's cut off in the sketch.
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
Why is it that .... the 4 is moved outside the limit?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.2
multiplied by 4x in num and denom, and it can be seen,iguess
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.2
the 4 is constant and constants can be moved outside the limit
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
dw:1347163083569:dw
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
Sorry, I meant 4x
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
so 12x/sin3x
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.2
now 12x / sin 3x can again be written as 4 * (3x/sin 3x) and using same limit again its 4*1= 4 ok?
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.1
dw:1347163221313:dw
 2 years ago

rainbow22 Group TitleBest ResponseYou've already chosen the best response.0
Oh, I get it now! Thank you guys SO MUCH!
 2 years ago
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