- Sat Apr 01, 2017 6:58 pm
#64494
So I decided to create the trigonometric functions that I need for a project with a celerometer and a gyroscope following the link
https://github.com/nodemcu/nodemcu-firmware/issues/1280.
When I create the arcsin function I am not getting the correct values for the calculated values (-1 to 1) in this function using the series equivalent to the arcsin function of this link
https://en.wikipedia.org/wiki/Inverse_t ... _functions. The
dfp and
dfi functions represent the double factorial functions to even and odd numbers for the calculation of the series. I hope and can help the development of this function.
regards
Here my code
Code: Select allfunction sin(x)
local p=-x*x*x
local f=6
local r=x+p/f
for j=1,60 do
p=-p*x*x
f=f*2*(j+1)*(j+j+3)
r=r+p/f
end
return r
end
function cos(x)
return sin(math.pi/2-x)
end
function tan(x)
return sin(x)/cos(x)
end
function arcsin(x)
local suma=x
for i=1,60 do
suma = suma + (dfi(2*i-1)/dfp(2*i))*(math.pow(x,2*i+1)/(2*i+1))
print("Suma: "..suma)
end
return suma
end
function dfp(x)
local par=1
for i=2,x,2 do
par = par * i
end
return par
end
function dfi(x)
local impar=1
for i=1,x,2 do
impar = impar * i
end
return impar
end
Note that when generating an approximation with 60 values like sin function, the result does not get close to the correct one and if it increases near 200, the card will restart itself.
regards
, is there any way to activate the basic functions, such as trigonometric from the lmathlib.c file?
