i don't get increasing and decreasing Inequalities. core1

hii

i have a mock exam on tuesday for maths alevel, the only thing i don't understand is increasing and decreasing Inequalities. i have looked on internet but itss soo confusing. can anybody help me or give me a good website/video which explains quite good.

for example
2x^2-5x+3<0 (2x-3)(x-1)<0 i don't understand the graph and all that

thanksss

Reply 1

TenOfThem

18

Original post by noor ul sabah

hii

i have a mock exam on tuesday for maths alevel, the only thing i don't understand is increasing and decreasing Inequalities. i have looked on internet but itss soo confusing. can anybody help me or give me a good website/video which explains quite good.

for example
2x^2-5x+3<0 (2x-3)(x-1)<0 i don't understand the graph and all that

thanksss

When you say that you do not understand the graph, are you saying that you do not know what the graph of

y=2x^2-5x+3

looks like?

Sketch the graph of

y=(2x-3)(x-1)

.

It is really easy to do so. It is a positive parabola that crosses the x axis in two places (where?).

Now look at this graph. For which x values are the y values negative (less than 0)?

Reply 3

aps74

OP

1

Original post by TenOfThem

When you say that you do not understand the graph, are you saying that you do not know what the graph of

y=2x^2-5x+3

looks like?

no the bit when you look at the graph and see if its increasing or decreasing!

Reply 4

TenOfThem

18

Original post by noor ul sabah

no the bit when you look at the graph and see if its increasing or decreasing!

That is not what this question is about

This is asking when is the graph<0

Original post by noor ul sabah

no the bit when you look at the graph and see if its increasing or decreasing!

You can't tell when a graph has a positive or negative gradient?

A positive parabola has this shape:

U

It decreases until it reaches the minimum point and then it increases. The x value of the minimum point is the mean of the two roots.

Reply 6

aps74

OP

1

Original post by Mr M

You can't tell when a graph has a positive or negative gradient?

A positive parabola has this shape:

U

It decreases until it reaches the minimum point and then it increases. The x value of the minimum point is the mean of the two roots.