College Math for 11-Years-Olds

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Science  08 Sep 1967:
Vol. 157, Issue 3793, pp. 1123
DOI: 10.1126/science.157.3793.1123


In my letter, "College math for 11-years-olds" (28 July), I stated that "it was apparent after a while that parabolas and hyperbolas could sometimes fall into circles and ellipses or vice versa." This is not true! Under any nonsingular linear transformation parabolas become parabolas, hyperbolas become hyperbolas, and ellipses become ellipses become ellipses (or circles).