QUERY22

course MTH 272

05/08,1830

assignment #022022.

Applied Calculus II

05-05-2010

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21:42:45

Query problem 7.1.24 picture of sphere, diam from (-1,-2,1) to (0, 3, 3).

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RESPONSE -->

Diameter =sqrt ( (0 - -1)^2 + (3 - -2)^2 + (3 - 1)^2)

Diameter=sqrt(30)

Diameter=Radius * 2

Radius= (sqrt(30))/2

MP of diameter equals center of sphere

MP=( (-1 + 0)/2 , (-2 + 3)/2 , (1 + 3)/2 )

MP=( (-1/2), (1/2), 2)

Equation of sphere:

(x - (-1/2))^2 + (y - (1/2))^2 + (z - 2)^2= (30/4)

confidence rating #$&* 2

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21:43:31

What is the standard form of the equation of the pictured sphere?

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RESPONSE -->

(x - (-1/2))^2 + (y - (1/2))^2 + (z - 2)^2 = (30/4)

confidence rating #$&* 2

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21:44:17

How did you find the center of the sphere?

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RESPONSE -->

Center of the sphere was found by finding the midpoint of the diameter. Accompanying work found with first part of question.

confidence rating #$&* 3

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21:44:52

How did you find the radius of the sphere?

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RESPONSE -->

Radius of the sphere was found by finding the distance of the diameter and then dividing this value by 2.

confidence rating #$&* 3

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21:53:37

Query problem 7.1.39 (was 7.1.38) yz-trace of x^2 + y^2 + z^2 - 6x - 10 y + 6 z + 30 = 0

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RESPONSE -->

x^2 + y^2 + z^2 - 6x - 10 y + 6 z + 30 = 0

(x^2 -6x + 9) + (y^2 -10y +25) + (z^2 + 6z + 9)= -30

(x-3)^2 + (y-5)^2 + (z +3)^2= -30+9+25+9

(x-3)^2 + (y-5)^2 + (z +3)^2=13

yz-trace (x=0)

(0-3)^2 + (y-5)^2 + (z +3)^2=13

9 + (y-5)^2 + (z +3)^2=13

(y-5)^2 + (z +3)^2=4

(y-5)^2 + (z +3)^2=2^2

confidence rating #$&* 2

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21:54:56

What is the equation of the yz-trace of the given sphere and what shape does this equation define in the y-z plane?

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RESPONSE -->

Equation of the yz-trace:

(y-5)^2 + (z +3)^2 =2^2

This defines a circular shape on the yz plane with a radius of 2.

confidence rating #$&* 2

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21:55:52

What is the center and what is the radius of the circle?

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RESPONSE -->

Center (0,5,-3)

Radius =2

confidence rating #$&* 2

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21:58:36

What is the standard form of the equation of the circle?

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RESPONSE -->

(y - 5)^2 + (z - -3)^2=2^2

Standard form of equation of circle using y and z instead of the usual x and y since this is a yz-trace.

confidence rating #$&* 2

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