Online Course Discussion Forum

MC III Algebra Help

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MC III Algebra Help
by Kevin Song - Tuesday, July 19, 2022, 5:34 PM


For 3.21, I calculated the determinant, 

\( \Delta = (2(m+1))^2 - 4*1*(3m^2+4mn+4n^2+1) = 2m^2-2m+4mn+4n^2+1 \geq 0 \)

I simplified to \( (m-1)^2+(m+2n)^2 \geq 0 \)

but I don't know where to go from there since that doesn't tell you anything.

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Re: MC III Algebra Help
by Dr. Kevin Wang - Wednesday, July 20, 2022, 12:55 PM

Are you sure your discriminant is simplified correctly?  You canceled a negative number, and that reverses the direction of the inequality.