Two questions (1 Viewer)

[Winston]

What's the quickest method of finding the region say in those linear questions they just ask you

shade in the region so that it satisfy's the two equations blah blah

what's the quickest way of finding it?


Second question

How do you remember all the various types of discriminant types i.e.


Discrim = 0 - Equal roots

because they always name it so many things like

> 0 can be real or different roots etc



what's all the names they have for each one


thanks

 

[ballerinabarbie]

Originally posted by Winston
What's the quickest method of finding the region say in those linear questions they just ask you

shade in the region so that it satisfy's the two equations blah blah

what's the quickest way of finding it?

solve the 2 equations simultaneously and plot the points on a number line
pick a point either between these two points or outside the two points
sub in the point
if the answer is correct then u shade that region
if the answer is incorrect then u shade the other region (eg. if u test for between the points and it's wrong, then you shade outside the points)

hope that made sense

 

[crazylilmonkee]

i always try and sub (0,0) and that helps to say whether past that point it is negative or positive, depending on the question

 

[iambored]

for 2

= 0 one root
real
equal

<0 no roots (which is understandable, in the quadratic formula u can't have a minus under the sq.root)
also
imaginary
not real
etc.

>0 2 roots
therefore real,
unequal

perfect square - rational
not - irrational

u can just sort of remember them after a while

 

[iambored]

Originally posted by ballerinabarbie
solve the 2 equations simultaneously and plot the points on a number line

i do it differently

i get the inequality of one line, sub in (0,0) if possible, then see which side i should colour (if it satisfies, it's the 00 side)
u can shade it lightly in pencil

then i get the other inequality, and do the same thing
shade the appropriate side, and rub out the bits from the previous thing i did that you don't need

 

[ballerinabarbie]

hmmmm i think i'm totally confused for that question... i think i need an example of a question to explain how to do it... although i'm pretty sure what i do works?

 

[kimmeh]

Originally posted by Winston
What's the quickest method of finding the region say in those linear questions they just ask you

shade in the region so that it satisfy's the two equations blah blah

either do it graphically [like draw it up]
or i use this parabola mthod kind of thing..

depends what your question is.. the parabola is for curves.. [i guess u dont want that]

but for shading regions.. to check u;ve shaded the right region.. sub in a point into the equation. if it is true , then that is the region you shade... if it doesnt satisfy or is not true, then u shade the other region.....