fix: math fixed once more

Author: cosmic-cortex

docs/source/content/examples/bayesian_optimization.ipynb

@@ -100,7 +100,9 @@
    "source": [
     "## Optimizing using *expected improvement*\n",
     "During the optimization, the utility of each point is given by the so-called *acquisition function*. In this case, we are going to use the *expected improvement*, which is defined by\n",
+    "\n",
     "$$EI(x) = (\\mu(x) - f(x^+)) \\psi\\Big( \\frac{\\mu(x) - f(x^+)}{\\sigma(x)} \\Big) + \\sigma(x) \\phi\\Big( \\frac{\\mu(x) - f(x^+)}{\\sigma(x)} \\Big),$$\n",
+    "\n",
     "where $\\mu(x)$ and $\\sigma(x)$ are the mean and variance of the Gaussian process regressor at $x$, $f$ is the function to be optimized with estimated maximum at $x^+$, and $\\psi(z)$, $\\phi(z)$ denotes the cumulative distribution function and density function of a standard Gaussian distribution. After each query, the acquisition function is reevaluated and the new query is chosen to maximize the acquisition function. "
    ]
   },