- Wed May 20, 2015 12:39 pm
- Forum: Advanced Algebra ("pre-calculus")
- Topic: Finding an nth degree polynomial
- Replies:
**1** - Views:
**27**

Suppose the division of f(x) by x-5 gives a quotient Q(x) and remainder R of 23. (b) Suppose Q(9) = 4; find f(9) One may "plug in" to what has already been determined by the conditions of the exercise. The exercise provides that: . . . f(x)\, =\, q(x)(x\, -\, 5)\, ...

- Wed May 20, 2015 12:29 pm
- Forum: Intermediate Algebra
- Topic: Substituting a Zero into a negative variable
- Replies:
**6** - Views:
**29**

so i'm trying to substitute this (1x^2 + 0x + 1 = 0) into the quadratic formula here is a reference link for the quadratic formula: http://postimg.org/image/8wx31enwf/ the part i'm not sure about is.. substituting 0 where -b is... what exactly happens What happens is that, where the Formula has a &...

- Mon May 04, 2015 2:14 am
- Forum: Uncategorized
- Topic: How did Babylonians divide circle into 360 ?
- Replies:
**2** - Views:
**123**

How did ancient people divide circle into 360 ? equal parts It is quite possible that nobody knows; this information may have been lost. But one method might have started with inscribing a pentagon using only a compass and straightedge . This would split the circumference into five equal arcs, each...

- Wed Mar 25, 2015 11:57 am
- Forum: Advanced Algebra ("pre-calculus")
- Topic: Having difficulty with exponent equation
- Replies:
**1** - Views:
**347**

6561^{2x^2\, -\, x}\, =\, 27 This is what I started: 81^((x^2)-x)=3^3 Some steps appear to be missing. I believe, between the two lines above, you have converted the 6561 into 81^2. However, since the 2 does not factor out of 2x^2 - x, it cannot be "taken out" and applied to the base sepa...

- Fri Feb 27, 2015 4:04 pm
- Forum: Discrete Math
- Topic: Find two proofs for the identity
- Replies:
**4** - Views:
**694**

Using a combinatorial argument, prove the following identity: \binom{2n}{2}\,=\,2\,\binom{n}{2}\,+\,n^2 To use a "combinatorial argument", one must consider sets of elements. On the left-hand side: Consider a set with 2n elements, and pick two elements at a time. This may be done in C(2n,...

- Sun Feb 15, 2015 3:05 am
- Forum: Calculus
- Topic: Finding the derivative of arctan
- Replies:
**1** - Views:
**378**

y=arctan sqrt[(1+x)/(1-x)] what i did: let u= sqrt[(1+x)/(1-x)] du=1/2 [(1-x)/(1+x)]^1/2 [{(1+x)(-1)-(1-x)}/(1+x)^2]dx I solved this problem many times, but I don't get the right answer.... Where did you take the derivative of the inverse tangent? What did you get for your answer? What is "the...

- Fri Jan 30, 2015 7:37 pm
- Forum: Matrix (Linear) Algebra
- Topic: is A C B^T = B C^T A^T ?
- Replies:
**1** - Views:
**504**

I don't understand how A C B^T + B C^T A^T = 2 A C B^T This may be rearranged as: A C B T + B C T A T = A C B T + A B C T This results in: B C T A T = A B C T Two properties of transpositions are that the transpose of a transpose is the original matrix, and that the transposition of a product resul...

- Fri Jan 30, 2015 7:26 pm
- Forum: Advanced Algebra ("pre-calculus")
- Topic: Eigen Vaues and Eigen Vectors
- Replies:
**1** - Views:
**454**

The information at the link appears to be as follows: \left[ \begin{array} {rr} 50&-40\\-40&45 \end{array} \right] \,\left[ \begin{array} {cc} X_1\\X_2 \end{array} \right]\, =\, \lambda\,\left[\begin{array}{rr}2&0\\0&5 \end{array} \right] \,\left[ \begin{array} {cc} X_1\\X_2 \end{arr...

- Fri Jan 30, 2015 7:10 pm
- Forum: Geometry
- Topic: Line Geometry and Euclid proposition 4 and 8 in book I
- Replies:
**1** - Views:
**4487**

Is there a book which has axioms for geometry on a line? Possibly ("probably"?) not. However, some information is available, such as ( this ) online article. Most other resources appear to be quite advanced, usually treating one-dimensional "cases" of other topics, such as "...

- Wed Jan 28, 2015 1:03 pm
- Forum: Calculus
- Topic: Inverse Function for y = x^(m+1) + x
- Replies:
**2** - Views:
**542**

wan nini wrote:I...need to find the inverse function.

y=x^{m+1}+x

I can't think of any way to invert this. How did you arrive that this function? What was the original exercise? Thank you.