Math Help Forum - Pre-Calculus

Sequences

Ilsa — Fri, 20 Nov 2009 15:45:48 GMT

There are two infinite sequences:

(an)n≥1 : 1∙1, 2∙3, 3∙5, 4∙7,��..

(bn)n≥1 : 1∙3, 2∙5, 3∙7, 4∙9,��..

Find general formulae for the two sequences and find how many common elements they have.

Getting the value of a function

VNVeteran — Fri, 20 Nov 2009 03:30:59 GMT

the number of units sold for a certain product is N=1700ln(9t+7) where t is the number of years after the product is introduced. What are the expected sales 9 years after the product is introduced?

Messing with the bases of logarithms

3k1yp2 — Fri, 20 Nov 2009 02:55:57 GMT

(Headbang)if log base a of x =c , and log base b of x = d, then what is the general statement that expresses log base (ab) of x in terms of c and d? plz help.

Possible values of p

scrible — Fri, 20 Nov 2009 01:27:23 GMT

Hi, there is this problem that I got from another math book that is getting the better part of me. It saids that for what value of p does the equation . Can someone help me solve this problem. I use the formulabut I am still not getting it. Thank you in advance.

Finding K

scrible — Fri, 20 Nov 2009 01:22:59 GMT

The question asked to find the valuesof k if the line is a tangent to the circle. can someone please help me solve the equation.

quadratic function

zipy147 — Fri, 20 Nov 2009 01:14:12 GMT

http://i47.tinypic.com/2igxf.jpg

Can anyone explain to me how to write a function for this table? (Worried) I been spending hours on it but still cannot figure it out.

Trig/Pre-calc homework help plz!!

moose51 — Fri, 20 Nov 2009 01:04:20 GMT

ok she has given me a homework and i dont even know where to start. this is what it is: Josephus Flavius was a famous jewish historian of the first century at the time of the second temple destruction. During the Jewish-Roman war he got trapped in a cave with a group of 40 soldiers surrounded by Romans. The legend has it that preferring suicide to capture the jews decided to form a circle and proceeding around it to kill every third remaining person until no one was left. Josephus not keen to die quickly found the safe spot in the circle and thus stayed alive.

Find the safe spot in a circle of 40 soldiers 20 soldiers and 10 soldiers. Is there a pattern that can be used to find out the safe spot in a circle of any number?? please help anyone

Edit: One hint i got was that i must include this somehow into a table.

[SOLVED] Help with trig identities proof

83457 — Fri, 20 Nov 2009 00:24:19 GMT

I'm stuck on the trig identities proof and I was wondering if someone could get me started.

evaluate question

wolfhound — Thu, 19 Nov 2009 17:45:38 GMT

Hi
if f(x)=4x^3-10x^2+8 and
how can I evaluate f(-3)? do I need to change it to f'(x) ....(first derivative)?
Thanks

Factor num and dem

wolfhound — Thu, 19 Nov 2009 17:41:29 GMT

Hi
Could someone tell me how to factorise the numerator and denominator of this:

x^2+4x-6/x^2+7x+9

complex numbers proof help

riptorn70 — Thu, 19 Nov 2009 06:51:13 GMT

please can somebody help with this proof. It goes like this:
|2-z| = |z| if and only if Re z = 1

where z = a + bi

any help would be greatly appreciated.

finding x in this parabolas equation

leahx22 — Thu, 19 Nov 2009 05:44:55 GMT

okay i've got y and the size of the parabola but i need the number x for the question! thanks. need this ASAP as exam is tomorrow!!

20 = -0.222x(x -24)

Square root derivative

Bacterius — Thu, 19 Nov 2009 03:57:56 GMT

Hi, I'm trying to derivate this function : . I'm applying this principle : if then . So there I go :

Now I derivate :

But the book says that's not right and the answer should be :

Does anyone see when I went wrong ? Thanks a lot ...

partial fraction decomposition help

yoman360 — Thu, 19 Nov 2009 02:50:05 GMT

Please Help Me with a couple of short questions on INEQUALITIES.

heidithompson1990 — Wed, 18 Nov 2009 23:39:40 GMT

1) Find the range of values of k that give this equation no real roots.
a) (k + 1)x^2 + 4kx + 9 = 0

2) Show that x^2 + 2kx + 9 is >/ (more than or equal to) 0 for all real values of x, if k^2 /< (is less than or equal to) 9

Thank you very much - if you can show your workings to help me understand I'd be really grateful!