Rewriting an Expression Without Changing Its Limit

You'll learnto read zero over zero as an instruction rather than an answer, to clear it by factoring, by a conjugate or by watching a sign, and to tell a cancellation that removes one point from one that replaces the whole curve.

Plug a number into a fraction and sometimes the top and bottom both come out zero. That is not the answer and not a dead end: it means the two share a factor, and canceling it leaves a curve that agrees with the original everywhere except one point. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · A FACTOR, NEVER A TERM · v2

zero over zero is an instruction · cancel a factor, never a term

Before you start

What you're looking at

One graph. Pink is the expression as written, a dashed green stroke is what a valid rewrite gives, and red is what an invalid one gives.

The question

When plugging in gives zero over zero, what may you do to the expression, and how would you know if you changed it?

Step 1 / 12