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# AS Maths: What do these questions mean? watch

1. ii) Find the coordinates of the stationary point on the curve .

What the hell is the stationary point? Is that just ?

Also,

iii) For what values of x does increase as increases?

I bet that one is easy. I'm just really lazy.
2. A stationary point is where the gradient of the curve is 0. So find $\frac{dy}{dx}$ of . Then solve this equation for y = 0. Then substitute the x value you just got into the original equation to calculate the y value - these two coordinates are the coordinates of the stationary point.

The second question, what values of $\frac{dy}{dx}$ are positive - this is where the curve has an increasing gradient.
3. Stationary point occurs when dy/dx = 0, when y = f(x).

Therefore to find it; simply differentiate, set it equal to 0, solve.

Stationary point occurs when dy/dx = 0, when y = f(x).

Therefore to find it; simply differentiate, set it equal to 0, solve.

Don't know what you mean to be honest, sorry :P Differentiate?
5. (Original post by Dededex)
ii) Find the coordinates of the stationary point on the curve .

What the hell is the stationary point? Is that just ?

Also,

iii) For what values of x does increase as increases?

I bet that one is easy. I'm just really lazy.
Epic sig
6. Startonary point is anywhare where gratient = 0

So dy/dx of your equation =18X +18

0=18X +18
-18=18X
X=-1

Y=9-18-7 = -16

so yes first one is correct.

I havnt seen iii) in C1 before, which is odd. I have an idea which includes X>1 and X<number between -1 and -2
I would also like to know
Btw, lovin the sig
7. (Original post by Dededex)
Don't know what you mean to be honest, sorry :P Differentiate?
Differentiating is finding the gradient. The rule is times it by the power and then reduce the power by one.

E.g

9x^2 goes to 18x
18x goes to 18
and the value without an x just disappears
8. (Original post by Dededex)
ii) Find the coordinates of the stationary point on the curve .

What the hell is the stationary point? Is that just ?

Also,

iii) For what values of x does increase as increases?

I bet that one is easy. I'm just really lazy.
You don't know how to differentiate so I am guessing you have been taught how to complete the square?

A parabola with a positive coefficient of is U shaped so the stationary point will be a minimum.

Locate it by completing the square and applying your knowledge of graph transformations.

All the x values to the right of the minimum are where the graph is increasing.
9. (Original post by Dededex)
Don't know what you mean to be honest, sorry :P Differentiate?
1) sketch the curve

2) find the stationary point. this is the point where the gradient is 0. you will quickly work out that this is the minimum value the curve can take.

3) find out when the minimum value occurs. i would try and be cryptic about it, but **** it, complete the square.

4) from your graph, it will be obvious where the curve is increasing. the only extra information needed is the x coordinate of the stationary point, which you will have found previously.
10. (Original post by GottaLovePhysics! :))
Startonary point is anywhare where gratient = 0

So dy/dx of your equation =18X +18

0=18X +18
-18=18X
X=-1

Y=9-18-7 = -16

so yes first one is correct.

I havnt seen iii) in C1 before, which is odd. I have an idea which includes X>1 and X<number between -1 and -2
I would also like to know
Btw, lovin the sig
I am honored that people like my sig, hehe.

yeah I completed the square for the first one though but everyone else here has done dy/dx.

iii is the last question on this revision sheet we're doing and I don't get it.
11. (Original post by ziedj)
1) sketch the curve

2) find the stationary point. this is the point where the gradient is 0. you will quickly work out that this is the minimum value the curve can take.

3) find out when the minimum value occurs. i would try and be cryptic about it, but **** it, complete the square.

4) from your graph, it will be obvious where the curve is increasing. the only extra information needed is the x coordinate of the stationary point, which you will have found previously.
Aah yeah that's what I did before to get (-1, -16) just completed the square and I think it's right.

but the other question I really don't understand what it's asking me to do - what valyes of x does the equation increase as x increases...?
12. (Original post by Dededex)
Don't know what you mean to be honest, sorry :P Differentiate?
If you've not covered differentiation yet, don't bother learning this thread.

Let your teacher cover it first or ask her / him privately.

Differentiation is the process by finding the gradient of a curve.

The general rule is: multiply term by power and minus 1 from power.

3x^2; multiply 3 by 2 (power) and minus one from power (6x^(2-1))

If you've not covered differentiation yet, don't bother learning this thread.

Let your teacher cover it first or ask her / him privately.

Differentiation is the process by finding the gradient of a curve.

The general rule is: multiply term by power and minus 1 from power.

3x^2; multiply 3 by 2 (power) and minus one from power (6x^(2-1))

yep, we definitely haven't covered it yet so I don't know why it's in this revision sheet...
14. I have already explained how to do this question without differentiation ...
15. (Original post by Mr M)
You don't know how to differentiate so I am guessing you have been taught how to complete the square?

A parabola with a positive coefficient of is U shaped so the stationary point will be a minimum.

Locate it by completing the square and applying your knowledge of graph transformations.

All the x values to the right of the minimum are where the graph is increasing.
Aah I understand that but how do I notate the x values - basically how do I write an answer to the latter question; I know the minimum point is (-1,-16) from completing the square so far.
16. (Original post by Dededex)
I am honored that people like my sig, hehe.

yeah I completed the square for the first one though but everyone else here has done dy/dx.

iii is the last question on this revision sheet we're doing and I don't get it.
Yea unfortuanly you have to learn to diffrentiate, but for the moment you can complete the square.

And that iii) one is odd, so if anyone knows what to do (im looking at you, guy who got 10A*s) than let me know
17. You don't need to learn how to differentiate to find the maximum or minimum of a quadratic.

Anyway, how would you write all x values that are to the right of (-1, 16)?

Hint: use inequalities.
18. (Original post by GottaLovePhysics! :))
Yea unfortuanly you have to learn to diffrentiate, rather than competing the square.

And that iii) one is odd, so if anyone knows what to do (im looking at you, guy who got 10A*s) than let me know
Both myself and Mr M have explained not only how to solve the question using completing the square (meaning differentiation not required), but also explained part iii as well. (Well, his was more of an explanation, mine was more of an "it's obvious, draw a graph" type thing )
19. x > -1

Also never seen a question like that before. Guess we're only about 3 weeks into C1.
20. (Original post by ziedj)
Both myself and Mr M have explained not only how to solve the question using completing the square (meaning differentiation not required), but also explained part iii as well. (Well, his was more of an explanation, mine was more of an "it's obvious, draw a graph" type thing )
I thought your post was pretty clear actually.

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