- Fri Nov 25, 2016 7:40 pm
- Forum: Trigonometry
- Topic: Need help verifying an identity - sums and differences
- Replies:
**2** - Views:
**154**

Can anyone help me verify this identity? tan (a-b) = (1 - cot(a) tan(b)) / cot(a) + cot(b) they show how to do this stuff here: http://www.purplemath.com/modules/proving.htm the right hand side (RHS) is messier so try starting there see if maybe the fraction simplifies 1 - cot(a)tan(b) = 1 - cot(a)...

- Wed Oct 12, 2016 2:50 pm
- Forum: Beginning Algebra
- Topic: floor tiles: 12" by 12"; how many needed for 12ft by 31ft floor?
- Replies:
**6** - Views:
**223**

How many tiles will I need when covering a floor which measures 12ft by 31ft. The tiles are 12 inches by 12 inches. there are 12" in 1' so the tiles are 1' by 1' or 1' square. my steps so far: 12 x 31 = 372 now since the tiles are in inches I need to convert that 372 feet into inches. so 372 x...

- Fri Aug 19, 2016 7:07 pm
- Forum: Trigonometry
- Topic: Given that ×=tan theta find arcot x in terms of theta
- Replies:
**1** - Views:
**456**

Given that × = tan(@), find arcot(x) in terms of @ i'm using "@" for "theta" do the regular placeholder triangle: triangle: . , '| , ' | , ' | x , '@ | *----------------* 1 so tan(@) = x/1 = x every triangle has 180* angle sum & this is a right triangle get an expression in ...

- Thu Jul 28, 2016 3:48 pm
- Forum: Uncategorized
- Topic: Where to start?
- Replies:
**1** - Views:
**720**

they should give you a placement test so they start you out where you need to be based on what you remember: http://www.purplemath.com/modules/placment.htm since only you (or a test) can know what you remember only you (or the test) can say where you need to start. you have to go back to whatever yo...

- Mon May 30, 2016 2:18 pm
- Forum: Intermediate Algebra
- Topic: Graphing calculator resources?
- Replies:
**1** - Views:
**542**

I'm trying to follow along on some of the examples using a TI-84 plus calculator, and I can't get the graphs to come out the same as the examples. Only way I know how to graph quadratic equations is pressing "y=", filling out the equation, and hitting graph. Not sure what to search to eve...

- Fri May 20, 2016 5:27 pm
- Forum: Intermediate Algebra
- Topic: Work problem
- Replies:
**1** - Views:
**501**

How would I do the following work word problem? they show how here: http://www.purplemath.com/modules/workprob.htm Tom and Sam can finish a plowing job in two hours. Tom working alone can do the job in 7 hours. How long would it take Sam to finish the same job alone? do like they show: hours to com...

- Sat May 07, 2016 1:20 pm
- Forum: Matrix (Linear) Algebra
- Topic: find rotation matrix in n dimention
- Replies:
**2** - Views:
**894**

are you asking about what they talk about here? https://en.wikipedia.org/wiki/Rotation_matrix#Geometry

- Sat May 07, 2016 1:15 pm
- Forum: Trigonometry
- Topic: Trig Identity prob: show that cot^2x sinx/(1-sinx)(1+sinx) = 1/sinx
- Replies:
**1** - Views:
**351**

show that cot^2x sinx/(1-sinx)(1+sinx) = 1/sinx i'm taking your eqn to mean this: . . . . . \dfrac{\cot^2(x)\, \sin(x)}{(1\, -\, \sin(x))\, (1\, +\, \sin(x))}\, =\, \dfrac{1}{\sin(x)} use the way they show here: http://www.purplemath.com/modul...

- Sat May 07, 2016 1:01 pm
- Forum: Geometry
- Topic: Challenge: Finding the midline of an irregular shape
- Replies:
**1** - Views:
**499**

your links lead to something that asks for payment or installation of software.

i'm not doing either.

sorry.

i'm not doing either.

sorry.

- Wed Mar 30, 2016 5:11 pm
- Forum: Calculus
- Topic: Equation of a tangent line, did I do this wrong?
- Replies:
**1** - Views:
**474**

(a) By using the definition of the derivative, find y' if y = 6 - 2x - x 2 . (b) Find the equation of the tangent line to the curve at the point (1, 3). (c) Find the point(s) at which the tangent line is horizontal. Here is... my work: (a) -2 - 2x how did...