All of these equations space quadratics but they every have different roots. But what is a root??

A root is the x value when the y worth = 0. It’s wherein the graph the cross the x axis. Since y=x2+2 does not cross the x axis that does no have any roots. This is simple to watch graphically! same if we have a graph we have the right to simply review off the ivorycrimestory.comordinates that overivorycrimestory.comme the x axis to calculation the roots.

You are watching: How to find the turning point of a function

To occupational this the end algebraically however we use ivorycrimestory.commponent of the quadratic formula: b2 -4ac

If b2 - 4ac = 0 climate there will be one genuine root, one ar where the graph the cross the x axis eg. Y=x2

If b2 - 4ac > 0 There will certainly be two real roots, prefer y= -x2+3

If b2 - 4ac 2+2

We can present this algebraically as well:

Remembering the ax2+ bx + c is the standard layout of quadratic equations.

For y=x2 a= 1 b=0 c=0

b2 - 4ac

02 - 4(1)(0) = 0

0 - 0 = 0 thus there is one actual root.

For y = -x2 + 3 a=-1 b=0 c=3

b2 - 4ac =

02 - 4(-1) (3) = 12

12 >0 for this reason there room two genuine root.

For y=x2+2 a=1 b=0 c=2

02 - 4(1) (2) = -12

-12 2 + x + 6, to disivorycrimestory.comver our root we must make y=0.

Therefore 0 = x2 + x + 6

Factorise 0 = (x+3) (x-2)

So every bracket must at some point be equal to 0

0 = (x+3), -3 = x

0 = (x-2), 2 = x

Which is specifically what we deserve to see here:


Identifying turning points

The turning point the a graph is where the curve in the graph turns.



The turning point will ivorycrimestory.comnstantly be the minimum or the maximum worth of your graph.

To univorycrimestory.comver the transforming point that a quadratic equation we must remember a pair of things:

The parabola ( the curve) is symmetricalIf we understand the x worth we deserve to work the end the y value!

So mental these vital facts, the very first thing we have to do is to work-related out the x worth of the transforming point. Let’s job-related it v with the instance y = x2 + x + 6

Step 1: univorycrimestory.comver the root of her quadratic- do this by factorising and equating y ivorycrimestory.comme 0. (Exactly as we did over with Identifying roots)

Therefore 0 = y = x2 + x + 6

Factorise 0 = (x+3) (x-2)

So each bracket have to at some point be same to 0

0=(x+3), -3= x

0=(x-2), 2=x

Step 2: find the typical of the two roots to gain the midpoint the the parabola. This will provide us the x value of our turning point!

-3 + 2 / 2 = -½

Therefore x= -½.

Step 3: substitute x right into the original formula to disivorycrimestory.comver the value of y.

y= (-½)2 -½ - 6

=¼ -½ - 6

= -6.25

How plenty of roots does y= 3x^2+2x+6 have?Your answer need to include: none / Zero / 0What is the transforming point of x^2+5x+4?Your answer need to include: -2.5 / 22.75

Revision timetable.Done because that you.

See more: Id Walk A Mile For A Camel ? Not Far Enough Anymore; Smokers

Check the end Adapt — the A-level & GCSE revision timetable app.