Worked solution
Sketch three upper solution relations and qualify their endpoints
Show the general solution of , , is . On one diagram sketch the members with .
CJC · Lecture · Example 13
Integrate the relation
gives , hence with C=2A. Since y is nonnegative, use the upper square root where real.
Retain all three source members and calculator entries
The source enters (C=0), (C=−1), (C=1). For C=−1 the geometric x-intercepts are . For C=0 they are 0 and 1. The C=1 curve is smooth for all real x, with minimum and y-intercept 1.
Distinguish the plotted closure from a differentiable solution
For C=−1 and C=0, the zero-height endpoints are valid points of the implicit squared relation, but not classical differentiable solutions of the original equation there: at y=0, the left side would be 0 while 2x−1 is nonzero. The classical solution branches therefore use the open intervals beyond those endpoints; the displayed figure marks them open while retaining their limiting coordinates. The Teacher note labels family sketches as outside the stated examination syllabus; this exercise is retained as source enrichment rather than removed.
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Common mistakes
A plotted endpoint of an implicit relation need not admit a finite derivative satisfying the original equation.