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pka
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pka
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Join Date
01-29-2005
Last Activity
Today
11:39 AM
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pka
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Today,
12:05 AM
pka
replied to a thread
This one has me stumped - entrance exam for junior high school in Japan
in
Geometry and Trig
In Japan by grade six, students have a strong base in simple algebra.
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15 replies | 259 view(s)
Yesterday,
11:59 PM
pka
replied to a thread
If n is an integer between 1 and 96 (both included), what is the probability that n
in
Probability / Statistics
As an old testing guy this question really puzzles me. Even having worked with the GRE this just does not seem usual unless it was a time waster. Oh...
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12 replies | 140 view(s)
Yesterday,
11:17 PM
pka
replied to a thread
This one has me stumped - entrance exam for junior high school in Japan
in
Geometry and Trig
@Vancouverron, I wish you had posted your result. I think the the solution is really simple. Suppose that \bf{\mathcal{s}} is the length of the...
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15 replies | 259 view(s)
12-16-2018,
10:22 PM
pka
replied to a thread
Help with finding first level derivative of y = x^2 * 2^x^2
in
Calculus
If the question is D_x\left then all I can say if that is too advanced question for a beginner. First of all the question requires logarithmic...
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4 replies | 109 view(s)
12-16-2018,
02:34 PM
pka
replied to a thread
Hard progression: x0=1, x(n+1)=2x(n)+1, S(n)=x0+x1+...x(n). Find S(2018)
in
Intermediate/Advanced Algebra
You might find THIS useful.
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5 replies | 173 view(s)
12-15-2018,
10:26 PM
pka
replied to a thread
How to find the range of polynomial functions without knowing extrema?
in
Intermediate/Advanced Algebra
Let's rewrite f(x)=-5(2x+1)(x-2)^2(x-6) If x\in(-\infty,-0.5)\cup(6,\infty) then f(x)<0. Is that correct? Now if x\in(-0.5,6) then f(x)\ge 0, do...
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2 replies | 132 view(s)
12-14-2018,
10:46 PM
pka
replied to a thread
What is the primitive / anti-derivative of x^x ?
in
Calculus
Have a look HERE/
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2 replies | 130 view(s)
12-14-2018,
10:28 PM
pka
replied to a thread
how to simplify this radical fraction: 4th-root[ 225 / 81 ]
in
Intermediate/Advanced Algebra
O.K. fair enough smart-guy, what is your question then?
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19 replies | 477 view(s)
12-14-2018,
09:20 PM
pka
replied to a thread
how to simplify this radical fraction: 4th-root[ 225 / 81 ]
in
Intermediate/Advanced Algebra
3^2\cdot 5^2=9\cdot 25=225 You have problems with simple arithmetic of fractions. \large \sqrt{3^2\cdot 5^2}=\left(3^2\cdot...
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19 replies | 477 view(s)
12-14-2018,
03:34 PM
pka
replied to a thread
Logic Question
in
Advanced Math
Dan, that is inscrutable story. I have great familiarity with UNC. UNC along with UVA are considered the two southern "Public-Ivys". Please tell me...
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16 replies | 413 view(s)
12-14-2018,
03:19 PM
pka
replied to a thread
Indefinite integral w/ continous functions: f(x)={ 2x-1,x<=1} { x^2,x>1}
in
Calculus
Now find C_1~\&~C_2 -8=F(4)=\dfrac{4^3}{3}+C_2 so that -8=\dfrac{64}{3}+C_2 or C_2=-\dfrac{88}{3} \mathop {\lim }\limits_{x \to {1^ - }} \left(...
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13 replies | 350 view(s)
12-14-2018,
01:44 AM
pka
replied to a thread
how to simplify this radical fraction: 4th-root[ 225 / 81 ]
in
Intermediate/Advanced Algebra
If I were doing this, I would factor 225~\&~81. 225=3^2\cdot 5^2~\&~81=3^4 \begin{align*}\sqrt{\dfrac{225}{81}}&=\sqrt{\dfrac{3^2\cdot...
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19 replies | 477 view(s)
12-13-2018,
03:59 PM
pka
replied to a thread
Complex numbers: find ((1+i*sqrt(3))/(1-i))^80 in algebraic form.
in
Intermediate/Advanced Algebra
Although you have been asked to so work, having spent over an hour trying to get that answer I became convinced it was incorrect even though...
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3 replies | 180 view(s)
12-11-2018,
01:44 PM
pka
replied to a thread
Surd Problem
in
Intermediate/Advanced Algebra
The above reply begs the question: do you understand the operations with fractions? \dfrac{A}{B}-C=\dfrac{A-BC}{B}...
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15 replies | 425 view(s)
12-11-2018,
01:08 PM
pka
replied to a thread
Surd Problem
in
Intermediate/Advanced Algebra
\begin{align*}\dfrac{4\sqrt{3}}{\sqrt{3}}-2&=\dfrac{4-2\sqrt{3}}{\sqrt{3}}\\&=\dfrac{4-2\sqrt{3}}{\sqrt{3}}\left(\dfrac{\sqrt3}{\sqrt{3}}\right)\\&=...
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15 replies | 425 view(s)
12-11-2018,
11:36 AM
pka
replied to a thread
Hard Inverse function f(x) problem
in
Intermediate/Advanced Algebra
To wolly, you were repeatedly asked to supply the exact wording of the question. Had you done, this thread could have shorten considerably, Asking...
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15 replies | 511 view(s)
12-10-2018,
05:07 PM
pka
replied to a thread
Hard Inverse function f(x) problem
in
Intermediate/Advanced Algebra
You have been asked to post the exact wording. So this a guess. Have you been asked to find the value of the derivative of the inverse function at...
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15 replies | 511 view(s)
12-09-2018,
10:07 PM
pka
replied to a thread
recommendations?
in
Intermediate/Advanced Algebra
Functions and Graphs by Earl Swokowski is one of the best advanced college algebra ever written. There are some very good used copies available...
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21 replies | 563 view(s)
12-09-2018,
01:23 PM
pka
replied to a thread
Linear Equations: teacher distributes $2 among 20 children...
in
Beginning Algebra
@Tadams, for self-studying you did a good job translating the statement into symbolic form. As you do more of these I suggest that if you have an...
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5 replies | 383 view(s)
12-09-2018,
11:59 AM
pka
replied to a thread
Maths Angle: A surveyor measures the angle of elevation as 19 degrees....
in
Geometry and Trig
You posted this question in the Pre-Algebra Forum. But I see no way to solve it without using trigonometry functions. Do you know how to work with...
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2 replies | 276 view(s)
12-09-2018,
10:10 AM
pka
replied to a thread
Did my Prof mark my answer wrong in error? (set of vectors: lin. independent)
in
Advanced Math
Well I don't think I would have marked it completely wrong, but is is extremely confusing to read. Say if simply: The set S=\{v_1,v_2,v_3....v_k\}...
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5 replies | 210 view(s)
12-08-2018,
10:01 PM
pka
replied to a thread
Solving this quadratic equation on coordinate plane
in
Intermediate/Advanced Algebra
You know don't you that no one here angrily exclaimed anything to you. You seem to be projecting an attitude that is simply not there. So read this...
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25 replies | 880 view(s)
12-08-2018,
11:10 AM
pka
replied to a thread
Solving this quadratic equation on coordinate plane
in
Intermediate/Advanced Algebra
@Phavonic, I think we all here understand your frustration at this question. Frankly I am totally confused by it and taught mathematics for fifty...
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25 replies | 880 view(s)
12-07-2018,
09:59 PM
pka
replied to a thread
Solving this quadratic equation on coordinate plane
in
Intermediate/Advanced Algebra
Is your given task to solve 2x^2-4x+1=0~?. If it is then what does the other function have to do with that task? It seems that this is a simple...
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25 replies | 880 view(s)
12-06-2018,
11:32 PM
pka
replied to a thread
Simple Integral "Find what's wrong" question
in
Calculus
I agree with tkh that dx is totally irrelevant. This is a poor question, it is a bad 'grouping' question. \int {\left} = \int {fg} + 4\int h -...
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7 replies | 386 view(s)
12-06-2018,
02:54 PM
pka
replied to a thread
Quadrilateral Family: In nice and green valley there is a building with 4 floors...
in
Geometry and Trig
I find this to be a rather odd discussion. That is because the trapezoid seems to be the odd figure out. Although the trapezoid is a quadrilateral...
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13 replies | 711 view(s)
12-06-2018,
01:51 AM
pka
replied to a thread
Expected value: Suppose people randomly pick a number between 0 and 1....
in
Probability / Statistics
Suppose that N_1~\&~N_2 choices then if \{N_1,N_2\}\subset then N_1+N_2\ge1 and \mathcal{P}(N_1,N_2)=.25. BUT if \{N_1,N_2\}\subset then N_1+N_2<1,...
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13 replies | 714 view(s)
12-05-2018,
11:43 PM
pka
replied to a thread
two questions about: Let x,y,z be distinct, non-zero, one-digit numbers.
in
Pre-Algebra
Each of the three numbers is prime & one is even. Thus the selection is \{2,3,5\},~\{2,3,7\},\text{ or }\{2,5,7\} 7-3=4,\text{ or }7-5=2
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5 replies | 423 view(s)
12-04-2018,
08:15 PM
pka
replied to a thread
Help: Find line perpendicular to y=-2/3x-8/9 passing thru (6,-9)
in
Geometry and Trig
I am a strong proponent of using the general form of the line: Ax+By+C=0 Using that equation we can see at once the slope: \dfrac{-A}{B},~B\ne 0....
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7 replies | 358 view(s)
12-04-2018,
05:58 PM
pka
replied to a thread
Locus problem
in
Geometry and Trig
The equation of the line \ell: \overline{AB} is 7x+4y-23=0. Now if the point C ; (p,q) the distance d(\ell,\overline{AB}) from \ell \text{ to...
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8 replies | 345 view(s)
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About pka
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About pka
Biography:
Retired university mathematics professor & division chair.
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“A professor is someone who talks in someone else’s sleep”
W.H. Auden
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Last Activity
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11:39 AM
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01-29-2005
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