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# Help with FP3 further coordinate systems question watch

1. Could someone explain the answer to part d? I managed the y axis part, but I don't get the inequalities.

2. so the two tangent points are on the ellipse one directly above the other. the tangent lines will cross at a point on the x axis ( because the ellipse has the x axis as a line of symmetry ). so the locus will be the part of the x axis outside the ellipse.
3. (Original post by moz4rt)
Could someone explain the answer to part d? I managed the y axis part, but I don't get the inequalities.
As varies, goes between -1 and 1, but since it is in the denominator, the fraction has range or . (look at the graph of ), and so then since we have , mult both sides by and we get that which implies that or . Since the x-coordinate of R is precisely , we get the inequalities.

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