Prompt
"Generate an image representing a normal distribution, also known as a Gaussian distribution, with a bell-curve shape, showcasing its characteristic symmetry and a peak at the mean (μ). The image should include a graphical representation of the probability density function (pdf) with the x-axis ranging from negative infinity to positive infinity and the y-axis representing the density. Incorporate the standard deviation (σ) and variance (σ²) notations. The style should be mathematical and graphical, suitable for a statistical concept. The image should not depict any person or population but rather a mathematical illustration."