[Wolves] OT: Maths problem

[chris procter]

 --- sparkes <sparkes at westmids.biz> wrote: 
> Andy Wootton wrote:
> > I'm also concerned about how much maths I've
> forgotten. I know you have 
> > the answer but I'm worried that I don't even
> understand what the diagram 
> > represents. What are the axes of the grid?
> 
> It represents a fictional 2d area.  Where each unit
> of volocity is 1 
> unit of length/ unit of time, and each unit on the
> x,y axis represent 
> one of the same unit of length.  Both of which are
> completely abstract 
> as this is a computer simulation of nothing in
> particular.

Think of the y axis as north/south and the x axis as
east/west you are facing north and move off at V
metres per second at an angle of A.

In 1 second you have moved V metres. How many metres
north of your starting point and how many metres east?

Because the X axis and Y axis are at right angles to
each other this comes down to simple trigonmetry (the
distance you've moved is the hypoteneuse of a right
angled triangle)

cos A= X/V
and
Sin A= Y/V

which means you are 
X=V * cos A metres east of your starting point
and
Y=V * sin A metres north

now make the jump to saying that as long as all the
distances are measured in the same units it doesn't
matter if they are metres, yards, or pixels on a
screen, and that north and south can be the top and
bottom of the screen (or anything else you like as
long as they are at right angles and 2D), and time can
be seconds, hours, billion years, or ticks of a cpu
clock and you have a general solution that applys to
sparkes problem just as well as any other.

Of course if you move for more then one unit of time
then you need to multiply the answer by that:-
X=Vt * cos A
and
Y=Vt * sin A

I'm concerned about how much maths I remember since
leaving uni in 96

chris 




	
	
		
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