Find the differential equation of all the circles which pass through the origin and whose centres lie on y-axis.

Explanation

To find the differential equation of all circles that pass through the origin and whose centers lie on the y-axis, we can follow these steps:

### Step 1: Write the equation of the circle
The general equation of a circle with center at (0, k) (where k is the y-coordinate of the center) and passing through the origin (0, 0) is given by:

\[ x^2 + (y - k)^2 = k^2 \]
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