How to calculate the area under each end of a sine curve

Question

Given this data set:

y<-c(-13,16,35,40,28,36,43,33,40,33,22,-5,-27,-31,-29,-25,-26,-31,-26,-24,-25,-29,-23,4)
t<-1:24

My goal is to c

Answer 1

This may not be the solution you are looking for, but you could try this:

# Create a new t vector but with more subdivisions
t2 = seq(1,24,length.out = 10000)

# Evaluate your model on this t2
y2 = predict(reslm2, newdata = data.frame(t = t2))

lines(t2[y2>=0],y2[y2>=0],col="red")

# Estimate the area where the curve is greater than 0 
sum(diff(t2)[1]*y2[y2>0])

# Estimate the area where the curve is less than 0
sum(diff(t2)[1]*y2[y2<0])