AS Maths: What do these questions mean?

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

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

ii) Find the coordinates of the stationary point on the curve $y = 9x^2 + 18x - 7$.

What the hell is the stationary point? Is that just $(-1, -16)$?

Also,

iii) For what values of x does $9x^2 + 18x - 7$ increase as $x$ increases?

I bet that one is easy. I'm just really lazy.

Don't know what you mean to be honest, sorry :P Differentiate?

ii) Find the coordinates of the stationary point on the curve $y = 9x^2 + 18x - 7$.

What the hell is the stationary point? Is that just $(-1, -16)$?

Also,

iii) For what values of x does $9x^2 + 18x - 7$ increase as $x$ increases?

I bet that one is easy. I'm just really lazy.

Don't know what you mean to be honest, sorry :P Differentiate?

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

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.

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))

Answer = 6x.

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 $x^2$ 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.

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, 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 )