I tried to train/fit ARIMA & Auto ARIMA model with sin pattern datasets but it gives an invalid prediction, even in the first data point is invalid/not meaningful at all. can I get the solution or someone helps me out? I truly need this fix.
const model = new ARIMA({
auto: true,
verbose: true,
});
model.train(trainDatasets);
const [preds, errors] = model.predict(testLen);
below is the plotted data.

I tried to train/fit ARIMA & Auto ARIMA model with sin pattern datasets but it gives an invalid prediction, even in the first data point is invalid/not meaningful at all. can I get the solution or someone helps me out? I truly need this fix.
below is the plotted data.