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saleem.kh
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Does the curve (x - a)^2 + (y - b)^2 = 16 intersect the Y axis?
1) a^2 + b^2 > 16
2) a = |b| + 5
I read this question on another forum but couldn't understand explanation of solution. Can anybody help me to solve it.
Here is the solution,
[spoiler]Given equation is an equation of a circle centered at with radius 4.
 Statement (1) by itself is insufficient. S1 says that the center of the circle is further than 4 units away from the origin but it doesn't specify whether the circle is far enough from the axis not to intersect it.
 Statement (2) by itself is sufficient. From S2 it follows that and thus the center of the circle is at least 5 units away from the axis. As the radius of the circle is only 4
units, we can conclude that the circle does not intersect the axis.
 The correct answer is B. Statement 2 is sufficient.[/spoiler]
1) a^2 + b^2 > 16
2) a = |b| + 5
I read this question on another forum but couldn't understand explanation of solution. Can anybody help me to solve it.
Here is the solution,
[spoiler]Given equation is an equation of a circle centered at with radius 4.
 Statement (1) by itself is insufficient. S1 says that the center of the circle is further than 4 units away from the origin but it doesn't specify whether the circle is far enough from the axis not to intersect it.
 Statement (2) by itself is sufficient. From S2 it follows that and thus the center of the circle is at least 5 units away from the axis. As the radius of the circle is only 4
units, we can conclude that the circle does not intersect the axis.
 The correct answer is B. Statement 2 is sufficient.[/spoiler]
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