Calculating degrees for angsizing

[Golden_Void]

I'm confused about how these formulas work. On calculation guide, the formula is:

2atan(tan(70/2)*(object size in pixels/screen height in pixels))

But then I see calcs like this that use the formula:

Object = 2atan(Object_Size/Panel_Height/tan(70/2)))


Simply substituting in the corresponding pixel numbers on wolfram alpha, I get 31.55 and 103.1 degrees, respectively, when the result of the actual calc was 44. So what am I doing wrong?

 

[Golden_Void]

BUMP ):<

 

[Antvasima]

You can ask LordXcano, DontTalk, The Living Tribunal1, or some other calc group members to comment here.

 

[Golden_Void]

You can ask LordXcano, DontTalk, The Living Tribunal1, or some other calc group members to comment here.

I've asked at least 3 different people already and I only got a response from two..

 

[DontTalk]

Object_Size/(Panel_Height/tan(70/2)) = (Object_Size/Panel_Height)*tan(70/2)

Brackets are important, but aside from that it's the same.

Edit: For the result from the calc, I get 45┬░, which I would assume lies in the realm of rounding error. No idea how you got your values.

 

[Amelia_Lonelyheart]

I've heard that apparently Wolfram Alpha messes up the Angsizing formula. I personally use web2.0, which seems to work just fine.

 

[Golden_Void]

For the result from the calc, I get 45┬░, which I would assume lies in the realm of rounding error. No idea how you got your values.

It was from Gywn's calc that I linked

And Wolfram messing up the formula is highly believable. Now, why did you rearrange the parentheses on the second formula, and how are they the same? I'm very out of touch with my trig.

And yes I got 45.3 degrees, the second (incorrect version) gave me about 80 degrees.

 

[DontTalk]

Now, why did you rearrange the parentheses on the second formula, and how are they the same?

Well, first your formulation 2atan(Object_Size/Panel_Height/tan(70/2))) misses a parenthesis.

It has to be 2atan(Object_Size/(Panel_Height/tan(70/2)))

That is simply a writing error (there was one closing bracket too much already)


So why is

Object_Size/(Panel_Height/tan(70/2)) = (Object_Size/Panel_Height)*tan(70/2)

true?

That is simply the general rule of how to divide through a fraction.

For all real numbers a,x,y

a/(x/y) = a*(y/x) = (a*y)/x


That is all I applied.

(And because of that 2atan(Object_Size/(Panel_Height/tan(70/2))) = 2atan((Object_Size/Panel_Height)*tan(70/2)) of course, since the stuff in the 2atan() parenthesis is the same)

 

[Golden_Void]

Ahh I gotcha, I feel like we've accomplished so much lol. That would also explain why the three parentheses formula had a missing one. Would such a small difference in angle really affect the calcs these were based on? And is there a way I can PM you to discuss a few more things?

 

[Antvasima]

@DontTalk Does any part of the calculations guide page need to be adjusted?

 

[Golden_Void]

@Antvasima I think DO NOT USE WOLFRAM ALPHA should be put in giant bold letters, I've been working this problem for days and didn't think to use another calculator lol.

Also @DontTalk if you're reading this take me under your wing pls

 

[DontTalk]

@Antvasima: I don't think so. Knowing how to use the calculator of ones choice is the obligation of the user.

@Unite My Rice: I have an activity of approx. 1.5 responses per day or something. So I really don't invest much time on here this days. So I definitely don't feel like teaching people, sorry.

 

[Antvasima]

Okay.

 

[Golden_Void]

You can close this now @Ant

 

[Antvasima]

Okay.