Vertigo-X said:
dany612 said:
Vertigo-X said:
chapset said:
lim θ->0 (cos θ tan θ)/ θ = lim θ->0 [cos θ(sonθ/cosθ)]/θ = lim θ->0 (sin θ)/ θ = using the hospital rule ( which mean you use a derivative on top and in the bottom) lim θ->0 (cos θ)/1= 1/1 = 1
θ is just an other variable here
for the second one I am not 100% sure for this one
I used those two trigo identity: 1+ tan^2(x)= sec^2(x)
sec(x)= 1/cos(x) so sec^2(x)= 1^2/cos^2(x)= 1/cos^2(x)
lim x->0 tan^2(x)/x = lim x->0 (sec^2(x)-1)/x
lim x->0 [sec^2(x)]/x - 1/x = lim x->0 [1/cos^2(x)]/x - 1/x = lim x->0 1/xcos^2(x) - 1/x using the hospital rule you get lim x->0 0/something - 0/1 = 0
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Not to be a nag, but it's L'Hopital's rule. I also fixed your trigonometric identity (it was tg^2(x) before).
Good ol' fashioned calculus!
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thanks vertigo and chapset. Okay I have one question this time it involves rationalization, something which I understand more fully. Anyhow this question has this triangle shape as a coefficent which I assume is Delta but I don't recall it's revalance to this:
find limit:
((x+∆x)^2-x^2)/∆x
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delta x is simply the small difference between one point along a curve and the next. As in ∆x = x2-x1
I suppose I could take a stab at it.
lim ∆x->0 [(x+∆x)^2-x^2]/∆x
lim ∆x->0 [(x^2+2x∆x-∆x^2)-x^2]/∆x
lim ∆x->0 [(x^2-x^2)+2x∆x-∆x^2]/∆x
lim ∆x->0 [2x-∆x]∆x/∆x
lim ∆x->0 2x-∆x = 2x
f(x) = x^2
lim ∆x->0 [f(x + ∆x) - f(x)]/∆x
AKA the derivative!
y = nx^m
dy/dx = (n*m)x^(m-1)
The derivative is the easy way to do it. :)
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Okay you lost me in the bolded. So what would be the limit?