Cannon Problem (200)

[Chance1234]

I know I posted this up before but I don

[pieterse]

Like this.....

[Chance1234]

fantastic ! thanks a lot

[HansV]

You might have asked your question in a reply in the previous thread. In fact, Steve (sdckapr) has already answered your question, but you are using a non-standard way of measuring the angle. Mathematicians start at the positive x-axis and count counter-clockwise (see attached picture). In your case, starting at the positive Y-axis and counting clockwise:

X = distance * SIN(RADIANS(angle))
Y = distance * COS(RADIANS(angle))

In the example, distance = 7 meters and angle = 116 degrees, so X = 7*SIN(RADIANS(116)) = 6.29 and Y = 7*COS(RADIANS(116)) = -3.07 (rounded to 2 decimals)

[Chance1234]

Saw steve's answer but couldnt quite grasp it, as i was doing something wrong somewhere which i wasnt sure was down to the way i posted the orgiginal question, hence the reposting.

why on earth do mathemticians do it counterclockwise ?

My next bit is now is wind resistance , off googling!

[HansV]

The reason that mathematicians measure angles counterclockwise is probably related to the standard coordinate system: positive x-axis points "East", positive y-axis points "North". Starting from the positive x-axis and going towards the positive y-axis, you turn counterclockwise. But in the end, it's just a convention.

[Chance1234]

This makes me wonder if Mathemticians are good maps readers,

Heres how my spreadsheet is going, I have yet to put in the "Direct Hit" coding and for an added element I am adding a Team of journalist wondering around as well to avoid,

This is expanding on my other post usesless things you can do in excel,

Please note I know the coding is dirty at the moment !

[Claude]

Next time round, instead of DELETING your original post which leaves all the answers to that post hanging in the wild, EDIT the post instead of starting a new thread, thanks. <img src=/S/exclamation.gif border=0 alt=exclamation width=15 height=15>

[HansV]

Steve,

If you substitute Angle = 0 in your formula, 90-Angle = 90, so Sin = 1 and Cos = 0, leading to X = distance and Y = 0 (disregarding p1 instead of pi)

I think <post#=242441>post 242441</post#> contains the correct formulas for Chance's coordinate system.

[pieterse]

My sample file further up this thread should be correct too...

[HansV]

Yes, of course. Sorry for not mentioning your post too <img src=/S/grin.gif border=0 alt=grin width=15 height=15>.

The formulas in your and my post are basically the same; the RADIANS function multiplies by PI()/180.

[sdckapr]

<P ID="edit" class=small>(Edited by sdckapr on 10-Apr-03 07:13. change/correct PI from P1)</P>If you want to "work with" your "degree syntax" use:

X = distance * SIN((90-angle)/180*pi())
Y = distance * COS((90-angle)/180*pi())

Where angle is the degrees with North = 0, East = 90, etc. The "90-Angle" puts it into the math standard and the "/180 * Pi()" converts to radians

Steve

[sdckapr]

Yes, I thought that is what he wanted.

In his "degree scheme" 90