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Thu Jul 28, 2011 2:42 am
Forum: Advanced Algebra ("pre-calculus")
Topic: Probability Involving 3 Coins
Replies: 5
Views: 6208

### Re: Probability Involving 3 Coins

this experiment follows a binomial distribution

$P(X=x)= {3\choose x}\cdot \left(\frac{1}{2}\right)^3$

where x is the number or heads
Tue Jul 19, 2011 3:10 am
Forum: Calculus
Topic: limit, x=>0, (1/x^3)(1/sqrt[x^2+1] - (1+ax)/(1+bx)) = l
Replies: 3
Views: 6038

### Re: limit, x=>0, (1/x^3)(1/sqrt[x^2+1] - (1+ax)/(1+bx)) = l

it doesn't look possible. I looked at the Taylor expansion of $\frac{1}{\sqrt{x^2+1}}\;-\;\frac{1+ax}{1+bx}$. Even with the best choice of a,b the expansion includes an $x^2$ term and therefore the limit would not exist
Mon Jul 18, 2011 5:07 pm
Forum: Calculus
Topic: help with evaluation
Replies: 2
Views: 2177

### Re: help with evaluation

how would i evaluate f(x+h)-f(x)/h and simplify if f(x)=x^2-2x. Please help.

$\frac{f(x+h)-f(x)}{h}=\frac{(x+h)^2-2(x+h)-(x^2-2x)}{h}$

$=\frac{x^2+2xh+h^2-2x-2h-x^2+2x}{h}$

$=\frac{2xh+h^2-2h}{h}$

$=\frac{h(2x+h-2)}{h}$

$=2x+h-2$
Thu Jun 23, 2011 6:27 pm
Forum: Intermediate Algebra
Topic: [SPLIT] solving y(y+1)(y+2)(y+3) = 7920
Replies: 3
Views: 1897

### Re: [SPLIT] solving y(y+1)(y+2)(y+3) = 7920

$7920 = 2^4\cdot 3^2\cdot 5\cdot 11=8\cdot9\cdot10\cdot11$

therefore $y=8$

also note ...

$7920=8\cdot9\cdot10\cdot11=(-8)\cdot(-9)\cdot(-10)\cdot(-11)=(-11)\cdot(-10)\cdot(-9)\cdot(-8)$

so $y$ could also be -11
Thu Jun 23, 2011 12:44 pm
Forum: Intermediate Algebra
Topic: [SPLIT] solving y(y+1)(y+2)(y+3) = 7920
Replies: 3
Views: 1897

### Re: [SPLIT] solving y(y+1)(y+2)(y+3) = 7920

$7920 = 2^4\cdot 3^2\cdot 5\cdot 11=8\cdot9\cdot10\cdot11$

therefore $y=8$
Fri Jun 10, 2011 6:50 pm
Forum: Intermediate Algebra
Topic: Substituting a negative integer for a variable... exponent
Replies: 3
Views: 2398

### Re: Substituting a negative integer for a variable... expone

I ran across this yesterday in a Pearson intermediate Algebra text. The problem presented in the text is in regards to graphing ordered pairs. An equation to express the relationship between the pair is given as; y = 4 - x 2 The solution requested is a graph x and y for all pairs where x is an inte...
Fri May 27, 2011 5:00 am
Forum: Trigonometry
Replies: 1
Views: 1832

Here is a trig question I need help solving (step by step walk-through would be the most beneficial)
Our teacher prefers that we only work on one side.

(1 - csc^2 x) / (1 + csc x) = (sin x - 1) / sin x
Use the fact that

$\csc(x)=\frac{1}{\sin(x)}$

then simplify.
Mon May 23, 2011 4:24 pm
Forum: Pre-Algebra
Topic: pre-algebra story problem
Replies: 1
Views: 2224

### Re: pre-algebra story problem

I need help so I can help someone else:) Brad wants to buy flowers for a friend with $33.00. The daisies are$1.00 each and th roses are \$2.00 each. He buys 3 more daisies than roses. How much did the roses cost? Let X=# roses then how many daisies are there (in terms of X)? What is the cost for th...
Fri May 20, 2011 4:20 am
Forum: Calculus
Topic: Rocket- Work Integration
Replies: 2
Views: 3978

### Re: Rocket- Work Integration

I get

$\int\limits_{0}^{3000}\left[3+\left(40-\frac{2}{1000}x\right)\right]dx$
Wed May 18, 2011 4:17 am
Forum: Intermediate Algebra
Topic: simplifying rational expressions
Replies: 2
Views: 1569

### Re: simplifying rational expressions

How do you simplify this? (4n^2-8)/(4n-4)I know the answer, I just need directions on how to solve it...
factor out a 4 from the top and bottom

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