completing the square (1 Viewer)

[grassrecords]

ok when do you need to do this ?

 

[Li0n]

hmm
locus questions

thats all i can think of at the moment, i doubt they'd ask a direct 'complete the square' in this g(x). However, its possible in question 1 but ide think they'll throw in a locus bonus so they save the number of questions asked or something.

 

[grassrecords]

so what would i have to do exactly... like what would a possible question be that relates to locus ?

 

[Iota]

You might be asked to determine what the locus actually is.

For example, you might be given

x^2+4x+y^2-14y=28

What is this, a circle, parabola, ellipse, hyperbola?

You complete the square to get:
(x+2)^2 - 4 + (y-7)^2 - 49 = 28
(x+2)^2 + (y-7)^2=81
So the locus is actually a circle of centre (-2,7) with radius 9.

And it's also possible that you could be asked to prove the quadratic formula (among other things), but I doubt it.

 

[velox]

u definately should know this. Completing the square is year 10 work.

 

[withoutaface]

I tend to just do it by inspection, rather than formally doing it. But yeah, generally only need to do it for circles, or complex numbers if you do 4u.

 

[grassrecords]

thanks!...........