course Mth 272 [ȸݝ܇ԾxGڐassignment #022
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01:08:52 Query problem 7.1.24 picture of sphere, diam from (-1,-2,1) to (0, 3, 3).
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RESPONSE --> first find the midpoint (-1+0/2,-2+3/2,1+3/2) = (-.5,.5,2) r= sqrt((-1+.5)^2 + (-2-.5)^2 + (1-2)^2) r=sqrt(7.5) so the standard equation is (x-(-.5))^2 + (y-.5)^2 + (z-2)^2 = 7.5 confidence assessment: 3
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01:08:59 What is the standard form of the equation of the pictured sphere?
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RESPONSE --> answered confidence assessment: 3
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01:09:13 How did you find the center of the sphere?
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RESPONSE --> using the midpoint equation confidence assessment: 3
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01:09:28 How did you find the radius of the sphere?
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RESPONSE --> using radius formula confidence assessment: 3
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01:27:32 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 --> first find center and radius (x^2-6x+9) + (y^2-10y+25) + (z^2+6z+9) = 13 (x-3)^2 + (y-5)^2 + (z+3)^2 = 13 so the center of the sphere is (3,5,-3) and the radius is sqrt(13). then find trace eqn, the shape is a circle. (x-3)^2 + (y-5)^2 + (z+3)^2 = 13 replace x with zero 9+ (y-5)^2 + (z+3)^2 = 13 (y-5)^2 + (z+3)^2 = 2^2 eqn of cirlce confidence assessment: 3
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01:27:39 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 --> answered confidence assessment: 3
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01:27:45 What is the center and what is the radius of the circle?
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RESPONSE --> answered confidence assessment: 3
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01:27:50 What is the standard form of the equation of the circle?
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RESPONSE --> answered confidence assessment: 3
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01:28:14 Query Add comments on any surprises or insights you experienced as a result of this assignment.
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RESPONSE --> This was pretty straight forward, i think i understood it well. confidence assessment: 3
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