Categories
Linear, Quadratic, and Exponential Models* Quadratic Functions Quadratic Functions Quadratics Radicals

Completing the Square, II

matt owen

 

Matt submits the above, and Matt writes, “I think it’s especially interesting that this student left the mistake on the board even though she had found the correct solutions by graphing in Desmos.  I’m not really sure if she did half of forty, or sqrt 4 and then stuck a zero on it (she wasn’t sure either).”

I vote for “half of 40.” You?

Categories
Complex Numbers Quadratic Functions The Complex Number System

Complex Roots and Quadratics

Here’s the work:

Can you make sense of it? What’s the cause of this mistake? How could you help?

Categories
Complex Numbers Quadratic Functions The Complex Number System Uncategorized

From complex roots to a quadratic equation

How did this student end up with the answer he did?  What does it seem that he knows about complex numbers?

Categories
G-GPE.2 Quadratic Functions Quadratic Functions

Equation of Parabola

From the student’s work, what can we infer that the student knows?  What is the student thinking? How would you help?