Answer: The equation of the circle is
Step-by-step explanation: We are given to write the equation of the circle with radius √13 units and center at the point (-9.3, 4.1).
We know that
the standard equation of a circle with radius r units and center at the point (h, k) is given by
In the given circle,
radius, r = √13 units and center, (h, k) = (-9.3, 4.1).
Therefore, the equation of the circle will be
Thus, the equation of the circle is
Answer:
(-y, x)
Step-by-step explanation:
See the image attached.
We start with (x,y), this is, x in the abscissa axis and y in the ordinates axis. When we rotate it 90 degrees clock wise, the measure on the ordinates goes to the abscissa while the abscissa goes to the ordinates. You have to notice that this last movement is to the negative part of the ordinate axis. Here we pass from (x, y) to (y, -x).
Then you rotate again, going to a 180 degrees rotation in total. The movement is the same: ordinates values go to the abscissa value. So, the -x that was on ordinates goes to the abscissa and the y in the abscissa goes to ordinates. However this last movement implies a negative sign in the y value, as we are going from positive to negative values. So, we pass from (y, -x) yo (-x, -y).
Finally we move again for reaching the 270 degrees rotation. Similar to the last 2 movements, -x passes from abscissa to ordinates and becoming x as we the sign is positive. In the same way, the -y in the ordinates goes to the abscissa and still being -y as we still on negative values. So, we finish with (-y, x).
So, this is the final answer: (-y, x)
Here I also attach a numerical example.
