In each of the following Exercises 10 to 20, find the equation for the ellipse that satisfies the given conditions: Centre at , major axis on the y-axis and passes through the points and .
The equation of the ellipse is
or
Explanation
This question requires finding the equation of an ellipse with centre at origin and major axis along y-axis. The standard form for such an ellipse is , where is the semi-major axis.
Since the ellipse passes through two given points, we substitute these coordinates to get two equations in terms of and .
Solving these simultaneous equations gives us the values of and , which are then substituted back to get the final equation.
Solution Steps
Step 1: Since the centre is at and major axis is on the y-axis, the standard equation of the ellipse is
where is the semi-major axis and is the semi-minor axis.
Step 2: Since the ellipse passes through point , substituting and :
Step 3: Since the ellipse passes through point , substituting and :
Step 4: Let and . Then equations (i) and (ii) become:
Step 5: From the second equation, . Substituting in the first equation:
which gives
so
therefore
Step 6: Then
Thus and .
Step 7: The required equation of the ellipse is