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lim((sinпx-cosпx)/(16 * x ^ 2 -1)) when x --->0.25
(п=pi)

2007-12-20 06:37:49 · 9 answers · asked by HM H 2 in Science & Mathematics Mathematics

9 answers

LH rule
limit = π*(cosπx + sinπx) / (32x)
= π*(2/√2) / 8
= π√2 / 8

2007-12-20 07:29:03 · answer #1 · answered by Dr D 7 · 1 0

(pi*sqrt(2))/8, or 0.55536

If you evaluate it as is, you get 0/0. Thus, you need to use l'Hôpital's rule and take the derivatives of the numerator and denominator; these become the new numerator and denominator. The new fraction is (ncosnx+nsinnx)/(32x) where n=pi. Then take the limit of the new fraction as x --->0.25, (this limit is equal to the limit of the original), and the answer you get is (pi*sqrt(2))/8, or 0.55536

2007-12-20 06:52:43 · answer #2 · answered by retired_dragon 3 · 0 0

We can find this limit with the Hospital' rule :

the limit of the numerator and the denominator are 0, then the limit is equal to the limit of :

(sin(pi x) - cos(pi x))' / (16x²-1)'
= pi(cos(pi x) + sin(pi x)) / 32x

so, the limit is pi[sqrt(2)/2+ sqrt(2)/2] / (32/4)
=pi sqrt(2)/8

2007-12-20 06:47:53 · answer #3 · answered by Nestor 5 · 1 0

For difficult limits try l'hopital's rule i.e. look at f'(x) / g'(x)

Here f'(x) = pi cos(pix) + pi sin(pix) and
g'(x) = 32x
now limit of f'(x) / g'(x) = pi*sqrt(2) / 8

2007-12-20 06:51:45 · answer #4 · answered by lienad14 6 · 0 0

Nope, answer is pi/(4 sqrt(2))

Use l'Hopital's Rule

d/dx (sin (pi x) - cos(pi x)) = pi(cos(pi x) -sin(pi x))

d/dx(16x^2 -1) = 32x

Substitute x = 1/4

= pi/sqrt(32)

2007-12-20 06:54:55 · answer #5 · answered by David G 6 · 0 1

My first decision may be...18 inches. My mom continuously recommended me to flow with my 1st instinct (decision), she'd say, "you will continuously be perfect!" And ninety 8% of the time i'm. good success!

2016-11-23 17:47:08 · answer #6 · answered by ? 4 · 0 0

If you know of L"Hospital's Rule then it is the same limit as [n cos(nx) + n sin(nx)] / [ 32x]....n sqrt2 / 8

2007-12-20 06:48:51 · answer #7 · answered by ted s 7 · 0 0

yes thats so easy its your mom

2007-12-20 06:46:33 · answer #8 · answered by Anonymous · 0 1

it is solved by direct substitution.the answer is zero

2007-12-20 06:45:43 · answer #9 · answered by Anonymous · 0 3

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