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#1 Help Me ! » Arrangements » 2008-06-16 19:17:13

djbip
Replies: 1

How many distinct 5 letter words cand be made by using letters in the word "LINDSAY"  if:

a) there are no restrictions
b) D may not be used
c) D must be used

I need help please!
Thank You!

#2 Help Me ! » Help On Doing Graphs! » 2008-06-05 15:36:09

djbip
Replies: 0

i'm supposed to do a velocity-time, acceleration-time and distance-time GRAPH for a roller coaster.
does anyone know how the graphs are supposed to look? because i really have no idea

http://www.rcdb.com/ig59.htm?picture=3   this is the rollercoaster that i'm supposed to use.

I NEED HELP.
PLEASE.

#3 Help Me ! » Excel Help » 2008-06-02 16:18:46

djbip
Replies: 2

does anyone how can I graph a linear regression equation and a non-linear regression in excel. I know it's possible, i just don't know how to do it. I also want the equation the show on my graph?

Can anyone please help me?

And also, I'm not sure about this one, but is it possible to find the interquartile range using excel??

Thank You!

#4 Re: Help Me ! » A few trig questions » 2008-05-29 08:58:36

djbip

Can someone please solve them for me?

I knew about the identity before I posted. I just don't know if I got the right results.
I'm not asking about the method, I asking about the right result.

#5 Help Me ! » A few trig questions » 2008-05-29 08:33:27

djbip
Replies: 5

1)  2cosx - 4sin²x=0

I found cosx = 0 and sinx= -0.25. Is it right?

2)  sinx + 1 - 2cos²x=0

3) cos²x + sinx +1=0

#6 Help Me ! » A few other trig questions » 2008-05-25 13:32:47

djbip
Replies: 3

sinθ=cosθ 

sinθ-2cosθ=0

secθ=4secθ 

period 0 ≤ x ≤ 360°

I'm sorry, i know this is easy, but i don't seem to get it
Thanks!

#7 Help Me ! » Trig Question » 2008-05-25 11:30:42

djbip
Replies: 1

Solve

6cos²x + 7cosx - 3 =0   for period 0 ≤ x ≤ 360°

#8 Re: Help Me ! » derivatives » 2008-05-04 14:49:09

djbip
simron wrote:

1. Here's a hint: take the derivative, then set that equal to 1/2. Now just solve for x and then plug in x for y.

k...i got it! thanks!
but what about the other one?!
and i need more than a hint on this one!:o

#9 Help Me ! » derivatives » 2008-05-04 12:50:27

djbip
Replies: 4

1.  Given  y= (-1)/(2x-1)²
     Determine the coordinates of the point on the graph where the slope of the tangent is 1/2.

2. Find the equations of the tangent and normal to the curve y= (x ³ - 2x + 4)²\³ (to the power of 2/3) at x=2
      (hint: i'm supposed to use the chain rule for derivatives)

Please help me!!
Thanks!!

#10 Help Me ! » easy logarithm that i can't solve! :P » 2008-04-20 15:53:10

djbip
Replies: 2

log x + log 8 = 2       (the base is 10)

i need to solve without the use of a calculator

#11 Re: Help Me ! » problem involving 2 planes » 2008-04-15 17:56:59

djbip

OK....can you please help me with one more. I would be forever grateful

Determine a vector equation of the line of intersection of the two planes

p1: 3x-y+4z-2=0 and p2: x+6y+10z+8=0

Thank you

#12 Re: Help Me ! » problem involving 2 planes » 2008-04-15 17:42:54

djbip

you solved that stuff and you're not familiar with this??

Ax + By + Cz +D=0 is the usual equations of a plane... where normal vector n=[A,B,C] and (x,y,z) is a point on the plane

Ax + By + Cz + D + k(A'x + B'y +C'z +D')=0 is called a " linear combinations of equations of planes"

still can't relate anything? tongue

#13 Re: Help Me ! » problem involving 2 planes » 2008-04-15 17:31:48

djbip
Dragonshade wrote:

The normal vector of x-y+2z+5=0 is  <1,-1,2>
The normal vector of 2x+3y-z-1=0 is <2,3,-1>
The cross product of <1,-1,2> and <2,3,-1> would be the directional vector of the line
So the direction vector of the line would be <-5,5,5>
Then we shall find a point which lies on the line
solving the group of equations of two planes
2x+3y-z-1=0
x-y+2z+5=0
make x=0, y=-3/5 , z=-14/5
The line would be  r= <0,-3/5,-14/5>+t<-5,5,5>
The plane which include the line would be
n*r=0
n must be perpendicular to the plane's(x+2y-2z=0) normal vector <1,2,-2>
n must be perpendicular to the line's directional vector <-5,5,5>
<x,y,z>*<1,2,-2>=0
<x,y,z>*<-5,5,5>=0
make y =1, get
n=<4,1,3>
<4,1,3>*<x,y+3/5,z+14/5>= 4x+y+3/5+3z+42/5=0
So the plane would be 4x+y+3z+9=0




Too much calculation... hope I didnt get it wrong
btw, I am bad at calculating

k...thanks! you got it right, no calculation mistakes. big_smile

listen...
if the two planes intersect in a line then the following equation would represent another plane that contains this line:

Ax + By + Cz + D + k(A'x + B'y +C'z +D')=0

can this formula be used to solve the question? it might shorten it..

#14 Help Me ! » problem involving 2 planes » 2008-04-15 16:42:41

djbip
Replies: 7

find the equation of the plane that passes through the line of intersection of the planes x-y+2z+5=0 and 2x+3y-z-1=0 and that is perpendicular to the plane
x+2y-2z=0

Anyone? please...

#15 Help Me ! » Vector problem » 2008-03-27 19:45:29

djbip
Replies: 2

Can someone please help me with the following problems.

1. "Find paramtric equations of the line that passes through the point of intersection of L1 and L2, and that is perpendicular to both."

L1: (x-4)/2=(y -8 )/3=(z+1)/-4
L2: (x-16)/-6=(y-2)/1=(z+1)/2

i know that the result for this one is a pretty ugly one...

2. "Find parametric equations of a line that intersects both L1 and L2 at right angles"

L1: [x,y,z]=[4,8,-1] + t[2,3,-4]
L2: (x-7)/-6=(y-2)/1=(z+1)/2


I need the results in max 8 hrs....after that it is useles!! I hope someone will be able to help me

Thank You!

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