Law of Sines through Free Pascal

[Orestaklos]

Hey all,

I've started learning the FreePascal through Lazarus and I recently bought some books with exercises on it.
I've been coping for 1 week with the Law of Sines but without result.
The writen program is below attached.

I would appreciate it, when you have a look.
Thanks.

[Nitorami]

Hi Orestaklos

What is the problem ? When compiling, the compiler takes you directly to the incorrect lines:

1.

Code: [Select]

resdegB:=arcsin(radtodeg(0,99));
0,99 is not a valid number, the compiler thinks you passed two parameters. Try 0.99.

2. getresdegB should be called Trig2.getresdegB

If I fix these, it works for me.

Note - you do not need the C style brackets as in
function getpart4():single;

Simply use
function getpart4:single;

[Orestaklos]

Oh that was great!
I corrected it as you have mentioned and it works!

Thank you a lot!

[Orestaklos]

hm..
something goes wrong, the result comes to 0.02 instead of 81.89

[User137]

Without thinking of deeper semantics, shuffling functions around gives what you expect:

Code: [Select]

resdegB:=radtodeg(arcsin(ressinB));

Code: [Select]

Result for B=sin^-1(0,99)= 81,89
Ok, if i recall the arcsin doesn't take angle for parameter, it returns one. Also all functions work as radians, therefore the returned angle must be converted to degrees.

[Nitorami]

Of course. It makes no sense to apply radtodeg or degtorad to the argument of arcsin, which is not an angle but a number between -1 and +1.

The result of arcsin() is an angle. It is in radians, and can be converted to degrees by radtodeg (and not degtorad!).

[mas steindorff]

Note - you do not need the C style brackets as in
function getpart4():single;

Simply use
function getpart4:single;

but the "()" do aid in code review telling the human reader that "getpart4" is a function, not a variable. it's not like your saving any keystrokes with autocompletion enabled...

[Orestaklos]

Thank you all for your great help!
I try my best to understand the language and with your help it makes it easier.