Gambas ONE

in gambas playground i typed:-


dim a as float
dim b as float
a=rad(90)

print sin(a)
print cos(a)

result:-

1
6.12323399573677E-17

What is wrong here?

Thanks.

looks correct to me

rad(90) is equal to 1/2 of pi = 3.14/2 = 1.5707

a = 1.5707 not 90 deg.

the rest is simple math.

what is it you are trying to do?

mugwump wrote: ↑Tuesday 10th August 2021 6:21pm print cos(a)

6.12323399573677E-17

Today Gianluigi (a member of italian forum) asked Minisini about the problem of this result.
Minisini replied:

" This is normal. Rad() uses the Pi constant, and floating point numbers are never 100% accurate. "

mugwump wrote: ↑Tuesday 10th August 2021 6:21pm
print cos(a)

result:-
6.12323399573677E-17

What is wrong here?

As has already been stated, these kind of rounding errors are to be expected on a digital computer.

3 points:-
- you will get the same result if you perform the same calculations in LibreOffice Calc (...on the same computer)
- the error is very, very small
- using something like;

myCosine = Cos(Rad(90)) 

...doesn't make much sense.
It would be better to code something like this;

myCosine = Round(Cos(Rad(90)),-10)

I hope this helps.


Edit; sorry, forgot the Rad

OK Thanks for that .
I need to brush up on my maths!