Autocorrelation may be detected by looking at a plot of the

Autocorrelation may be detected by looking at a plot of the residuals against time.

Solution

True, typically negatively correlated pattern is very easy to detect, it shows a quick zigzag pattern. Positive autocorrelation shows a slow zig-zag or a wave like pattern. We can also draw ACF/PACF patterns to see autocorrelation in residuals.