# Posts by Abbey(Please help)

Total # Posts: 33

**Math**

Nevermind. I figured it out

*May 5, 2010*

**Math**

Find an equation of the hyperbola with its center at the origin. vertices:(3,0)(-3,0) Foci (5,0)(-5,0) My answer was x^2/3 - y^2/22 = 1. I do not know how to find a.

*May 5, 2010*

**Math**

Test for symmetry with repsect to Q=pi/2, the polar axis, and the pole. r=16cos 3Q r=16cos(3pi/3 + 3h) = 16(cos3pi/2 3h- sin 3pi/2 sin h) cos 3pi/2 = 0 sin 3pi/2 = -1 Not symmetrical My teacher said that this was wrong!Why?

*May 5, 2010*

**Math**

Find the vertex, focus, and directrix of the parabola. x^2 - 2x + 8y + 9 = 0 x^2 - 2x +1 = -8y + 9+ 1 (x-1)^2 = -8(y-1.25) vertex:(1,1.25) focus:(1,-.75) directrix: y=3.25 My teacher said that I have sign errors. I do not know where I went wrong.

*May 5, 2010*

**Math**

The rectangular coordinates of a point are given. Find two sets of polar coordinates for the point for 0 is less than or equal to Q is less than 2pi. (-3,-3) My answers were (-3sqrt2, pi/4) and (pi/4, -3sqrt2). My teacher said that my answers have to be in quadrant 3. Is my ...

*May 5, 2010*

**Math**

My teacher said that I had sign errors. I do not see where I went wrong.

*May 5, 2010*

**Math**

Is this correct?

*May 5, 2010*

**Math**

Find the vertex, focus, and directrix of the parabola. x^2 - 2x + 8y + 9 = 0 x^2 - 2x +1 = -8y + 9+ 1 (x-1)^2 = -8(y-1.25) vertex:(1,1.25) focus:(1,-.75) directrix: y=3.25

*May 5, 2010*

**Math**

Find an equation of the parabola. vertex:(-1,2) focus:(-1,0) (x+1)^2 = 4p(y-2) (x+1)^2 = 0(y-2) (x+1)^2 = (y-2) Am I correct?

*May 5, 2010*

**Math**

Use a graphing utility to graph the function. Then use the trace or table feature to identify the limit. lim 5/x-2 x-->2 I know I posted this question before but I am still having a hard time doing this. I pressed the y= button and typed the normal equation in: 5/x-2. Is ...

*May 4, 2010*

**Math**

so the vertices would be (2, -1+sqrt5/2) (2, -1-sqrt5/2)?

*May 4, 2010*

**Math**

Find the center, vertices, foci, and eccentricity of the ellipse. 9x^2 + 4y^2 - 36x + 8y + 31 = 0 I know the center is (2,-1) For the vertices I had (3,-1)(1,-1) and the foci (3.8,-1)(.20,-1) and e = 1.80 but I think these are wrong.

*May 4, 2010*

**Math**

use Demoivre's Theorem to find the indicated power of the complex number. Express the result in standard form. (2+2i)^6 a=2 b=2 n=6 r=sqrt 2^2 + 2^2 = sqrt8 Q=7pi/4 (sqrt8)^6 = 512 512(cos 6/1 x 7pi/4) + i sin 6 x 7pi/4 512 (cos 21pi/2) + i sin (21pi/2) 512(cos pi/2) + i (...

*May 4, 2010*

**Math**

Would n be 14?

*May 4, 2010*

**Math**

Logs are stacked up in apile as shown in the figure. The top row has 15 logs and the bottom row has 21 logs. How many logs are in the stack? a1= 1+14=15 an= 7+14=21 s1=(n/2)(a1+an) (n/2)(15+21) = 18 How do I figure out the n?

*May 4, 2010*

**Math**

use Demoivre's Theorem to find the indicated power of the complex number. Express the result in standard form. (2+2i)^6 a=2 b=2 n=6 r=sqrt 2^2 + 2^2 = sqrt8 Q=7pi/4 (sqrt8)^6 = 512 512(cos 6/1 x 7pi/4) + i sin 6 x 7pi/4 512 (cos 21pi/2) + i sin (21pi/2) 512(cos pi/2) + i (...

*May 4, 2010*

**Math**

I am not sure what to change.

*May 4, 2010*

**Math**

Find the angle Q between the two vectors. u = 10i + 40j v = -3j+8k cos <10,40,0> <0,-3,8> / sqrt1700 sqrt73 cos(-120/sqrt1700 sqrt73) = .9072885394 arc cos (.9072885394) = 24.86 degrees. Is this correct?

*May 4, 2010*

**Math**

I have a TI-83 graphing calculator. How do you graph a polar equation on this calculator. Also how would I graph lim 5/x-2 x-->2 in order to find the limit?

*May 3, 2010*

**Math**

Find an equation of the ellipse with its center at the origin. center(0,0) foci(2,0)(-2,0) major axis=8 My answer is x^2/16 + y^2/15 = 1. Is this correct?

*May 3, 2010*

**Math**

Find the center, vertices, foci, and eccentricity of the ellipse. 9x^2 + 4y^2 - 36x + 8y + 31 = 0 My answer was: center=(2,1) v=(-2,10)(-2,-10) f=(-2,11)(-2,-11) e=11/3 Where did I make a mistake?

*May 3, 2010*

**Math**

Thank You

*May 3, 2010*

**Math**

Write an expression for the most apparent nth term of the sequence. Assume n begins with 1. 3,7,11,15,19 My answer was an= 3 +4n but this wrong.

*May 3, 2010*

**Math**

When trying to solve arctan(sqrt 567.2 / -459.6) my answer was -2.96. My teacher said that i handled the radical wrong. She said I have to square both numbers, then add them, and then find the square root. I am confused because you cannot take the square root of -459.6. Please...

*May 3, 2010*

**Math**

The rectangular coordinates of a point are given. Find two sets of polar coordinates for the point. (-3,-3)

*May 2, 2010*

**Math**

Determine whether f is continuous at x=c in the function. Use the 3 conditions of continuity to justify your answer. f(x) = x-1/x+1 c=-1 My answer is not continuous. Am I correct?

*May 1, 2010*

**Math**

Thank You!

*April 30, 2010*

**Math**

plot the point given in polar coordinates and find the corresponding rectangular coordinates for the point. (-1 , -3pi/4) I do not understand.

*April 30, 2010*

**Math**

I need to graph the polar equation 3 + 3cosQ and i need to create a table of values for r and Q. Could someone please explain how I would do this? Thank you!

*April 30, 2010*

**Math**

I need to give an example of a function with at least one removable and one non-removable discontinuity. I am not to sure how to do this. Please explain! Thanky you

*April 25, 2010*

**Math**

Thank You!!

*April 24, 2010*

**Math**

A painter working at 100 feet from the ground, drops his paint brush onto the street below. The function, s(t)=-16t^2+100, gives the height(in feet) of the paint brush as it falls to the ground. The velocity at time t=2 seconds is given by lim s(2)-s(t)/2-t t-->2 Evaluate ...

*April 24, 2010*

**Math**

A point in polar coordinates is given, Find the corresponding rectangular coordinates for the point. (r,Q) = (4, 3pi/2) I know that you are suppose to use x=r cos Q and y=sin Q but I do not know how to plug this in.

*April 17, 2010*

- Pages:
**1**