step = 0.05

x = seq(0, 42, step)

x=42-x

fx = 9*cos(x*pi/42)+9

Vinkel = 0

for(i in 1:length(fx)-1){

 Vinkel[i]=atan((fx[i+1]-fx[i])/step)

}
plot(x, fx)

grad = Vinkel*57.2957795

max = which.max(Vinkel)

print(Vinkel[max])

print(grad[max])