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MarkFL
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Today,
04:42
MarkFL
replied to a thread
BBCode For Username HTML Markup
in
vBulletin Products
Update - Version 1.3: SEO friendly links to user profiles. vBulletin's intrinsic username markup function used. Username matching is now...
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1 replies | 45 view(s)
Yesterday,
22:53
MarkFL
replied to a thread
Prove a number is divisible by a number?
in
Number Theory
Another approach would be to use the binomial theorem: 7^n-1=(6+1)^n-1=6\sum_{k=1}^{n}\left({n \choose k}6^{k-1}\right)
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7 replies | 81 view(s)
Yesterday,
14:51
MarkFL
replied to a thread
AlphaZero Crushes Chess
in
Chat Room
That's amazing! (Yes)
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2 replies | 38 view(s)
Yesterday,
14:38
MarkFL
replied to a thread
limit of a series
in
Calculus
As suggested, I would continue on your current path, but I wanted to show how I would approach the problem... I would begin by expressing the...
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3 replies | 44 view(s)
Yesterday,
11:59
MarkFL
replied to a thread
Need help with reversal of a calculation involving gravitational constant.
in
Pre-Algebra and Algebra
It's actually: G=\frac{rV_e^2}{2M}
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6 replies | 67 view(s)
Yesterday,
01:55
MarkFL
replied to a thread
Revenue and Cost and Profit Problem
in
Business Mathematics
To follow up: The axis of symmetry is: x=-\frac{48}{2(-2)}=12 We see that the profit function opens downward, and so the vertex is the...
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3 replies | 44 view(s)
December 10th, 2017,
12:30
MarkFL
replied to a thread
Revenue and Cost and Profit Problem
in
Business Mathematics
Another approach would be to express your profit function in vertex form: P(x)=-a(x-h)^2+k where: P_{\max}=k
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3 replies | 44 view(s)
December 10th, 2017,
00:57
MarkFL
replied to a thread
Revenue and Cost and Profit Problem
in
Business Mathematics
Your profit function is correct: P(x)=-2x^2+48x-108 Now, what I would do is find the axis of symmetry (since the vertex lies on this...
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3 replies | 44 view(s)
December 9th, 2017,
17:06
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
If the hyperbolic tangent factor goes to 1, then the terminal velocity $v_T$ must be: v_T=\sqrt{\frac{mg}{k}} Dimensional analysis shows that...
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13 replies | 165 view(s)
December 9th, 2017,
15:05
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
Yes, and so what does this tell you about the terminal velocity?
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13 replies | 165 view(s)
December 9th, 2017,
08:12
MarkFL
replied to a thread
Need help with reversal of a calculation involving gravitational constant.
in
Pre-Algebra and Algebra
Hello, and welcome to MHB, Edwin! (Wave) We are given: V_e=\sqrt{\frac{2GM}{r}} What do we get if we square both sides of the equation?
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6 replies | 67 view(s)
December 8th, 2017,
20:08
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
Yes, so what's the limit: \lim_{u\to\infty}\tanh(u)\,?
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13 replies | 165 view(s)
December 8th, 2017,
02:39
MarkFL
replied to a thread [SOLVED]
M2215b.08 Find the volume of the solid (shell meithod)
in
Calculus
Let's check your result using the washer method: V=\pi\left(\int_0^{\sin\left(\frac{\pi^2}{4}\right)}...
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8 replies | 97 view(s)
December 7th, 2017,
22:14
MarkFL
replied to a thread [SOLVED]
M2215b.08 Find the volume of the solid (shell meithod)
in
Calculus
You originally had the integrand correct, but when you corrected the limits, you changed the integrand such that the integral was still incorrect...
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8 replies | 97 view(s)
December 7th, 2017,
17:54
MarkFL
replied to a thread [SOLVED]
M2215b.08 Find the volume of the solid (shell meithod)
in
Calculus
Now, reverse the change you made to the integrand...
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8 replies | 97 view(s)
December 7th, 2017,
17:49
MarkFL
replied to a thread [SOLVED]
M2215b.08 Find the volume of the solid (shell meithod)
in
Calculus
Examine your limits of integration more closely...:)
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8 replies | 97 view(s)
December 7th, 2017,
14:28
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
No, I was thinking more along the lines of: \tanh(u)\equiv\frac{e^{u}-e^{-u}}{e^{u}+e^{-u}} What happens if you multiply that by: ...
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13 replies | 165 view(s)
December 7th, 2017,
13:44
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
Okay, now the given velocity function is dimensionally consistent, given that $k$ has units of mass per length (can you demonstrate this?). In...
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13 replies | 165 view(s)
December 7th, 2017,
13:29
MarkFL
replied to a thread
Require Edit Reason
in
vBulletin Products
Update - Version 1.3: Add ability to exempt all usergroups from being required to edit, to allow for the setting of pre-defined edit reasons...
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1 replies | 65 view(s)
December 6th, 2017,
21:13
MarkFL
replied to a thread
m2215b.14 Find the limiting velocity
in
Calculus
You've given a constant velocity here...
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13 replies | 165 view(s)
December 5th, 2017,
06:22
MarkFL
replied to a thread
Area between the curve and x axis
in
Calculus
Yes that's correct: W|A - area between x-axis and y=2/(x-1)-1 on Note: W|A returns a result in a different form, but is recognizable as...
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8 replies | 128 view(s)
December 5th, 2017,
04:49
MarkFL
replied to a thread
Logarithmic functions
in
Calculus
You can also apply: \log_a\left(b^c\right)=c\cdot\log_a(b) To find the carrying capacity $C$, I would write: C=\lim_{t\to\infty}P(t)
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2 replies | 52 view(s)
December 5th, 2017,
04:10
MarkFL
replied to a thread
Area between the curve and x axis
in
Calculus
For part b), you want the area which is a bit different from the definite integral. The definite integral $I$ of the difference between two functions...
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8 replies | 128 view(s)
December 4th, 2017,
22:38
MarkFL
replied to a thread [SOLVED]
Buoyant Force
in
Other Topics
I would use: Archimedes' principle Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid...
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1 replies | 64 view(s)
December 4th, 2017,
22:25
MarkFL
replied to a thread [SOLVED]
243.14.7.5 Find all local extreme values
in
Calculus
We are given: f(x,y)=2xy-3x+3y Identify the critical point(s): f_x(x,y)=2y-3=0\implies y=\frac{3}{2} f_y(x,y)=2x+3=0\implies...
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1 replies | 46 view(s)
December 2nd, 2017,
00:02
MarkFL
replied to a thread [SOLVED]
Average Density of Gasoline
in
Other Topics
To find the mass of the gasoline, I would write m_g=\rho V=\left(680\,\frac{\text{kg}}{\text{m}^3}\right)\left(\frac{1}{50}\text{...
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10 replies | 145 view(s)
December 1st, 2017,
23:29
MarkFL
replied to a thread [SOLVED]
Average Density of Gasoline
in
Other Topics
Yes, although I would write: V=\frac{407}{20000}\text{ m}^3 Now, we need to find the mass of the 20.0 L = 1/50 m³ of gasoline...we know the...
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10 replies | 145 view(s)
December 1st, 2017,
23:05
MarkFL
replied to a thread [SOLVED]
Average Density of Gasoline
in
Other Topics
1\text{ L}=1\text{ L}\cdot\frac{1000\text{ cm}^3}{1\text{ L}}\cdot\left(\frac{1\text{ m}}{100\text{ cm}}\right)^3=\frac{1}{1000}\text{ m}^3 And...
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10 replies | 145 view(s)
December 1st, 2017,
22:43
MarkFL
replied to a thread [SOLVED]
Average Density of Gasoline
in
Other Topics
I think you have the volume inverted...I would write: V=\frac{m}{\rho}=\frac{2.80\text{...
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10 replies | 145 view(s)
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