Please help, some easy math problems
Favorites|Homepage
Subscriptions | sitemap
HOME > > Please help, some easy math problems

Please help, some easy math problems

[From: ] [author: ] [Date: 12-02-27] [Hit: ]
To solve this problem, you have to complete the square on the x and y terms. I wont go through the process,Leaving you with a radius of r = √81 = 9.For the second one, are you knowledgeable about vectors,......
Okay so i am having some trouble with a few problems.

What is the radius of the circle whose equation is x^2 + y^2 +18x + 12y + 36=0
1)9
2)3*radical 17
3)81
4)153

Next Problem:

What is the magnitude of the vector resulting from graphing the complex number 3-4i?

1) -5
2) radical -5
3) radical 5
4) 5

Please help even if you can only answer 1 of them, i would greatly appreciate it!

-
The standard form of the equation of a circle is:

(x - h)^2 + (y - k)^2 = r^2
where r is the radius and (h, k) is the center.

To solve this problem, you have to complete the square on the x and y terms. I won't go through the process, but the end result is:

x^2 + y^2 + 18x + 12y + 36 = 0
⇔ (x + 9)^2 + (y + 6)^2 = 81

Leaving you with a radius of r = √81 = 9.

For the second one, are you knowledgeable about vectors, in general? The graph of a complex number is just a vector with the real part as the horizontal component and the imaginary part as the vertical component. In other words,

3 - 4i = <3, -4>

The magnitude is then just the distance from (0, 0) to (3, -4). If you know your Pythagorean triples, then you should recognize the magnitude as 5. If not, applying the Pythagorean theorem (aka distance formula):

|3 - 4i|
= √(3^2 + 4^2)
= √25
= 5

Since magnitude is distance, we don't use negative numbers, so -5 would be an unacceptable answer.
1
keywords: problems,some,help,math,Please,easy,Please help, some easy math problems
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .