Fix equations

Author: mEngstroem

docs/src/tutorials/fitting/material_solvated.ipynb

@@ -152,32 +152,11 @@
    "source": [
     "So for the `solvated_film` object, the scattering length density is calculated as,\n",
     "\n",
-    "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\">\n",
-    "\n",
-    "  <mi>ρ</mi>\n",
-    "  <sub>\n",
-    "    <mi>solvent</mi>\n",
-    "  </sub>\n",
-    "  <mo>=</mo>\n",
-    "  <mo>(</mo>\n",
-    "  <mn>1</mn>\n",
-    "  <mo>-</mo>\n",
-    "  <mi>ϕ</mi>\n",
-    "   <sub>\n",
-    "    <mi>film</mi>\n",
-    "  </sub>\n",
-    "  <mo>)</mo>\n",
-    "  <mo>+</mo>\n",
-    "  <mi>ϕ</mi>\n",
-    "  <mi>ρ</mi>\n",
-    "  <sub>\n",
-    "    <mi>D</mi>\n",
-    "    <sub>\n",
-    "    <mn>2</mn>\n",
-    "    </sub>\n",
-    "    <mi>O</mi>\n",
-    "  </sub>\n",
-    "</math>\n",
+    "$$\n",
+    "\\begin{aligned}\n",
+    "\\rho_{solv film} = (1-\\phi)\\rho_{film} + \\phi\\rho_{D_2O},\n",
+    "\\end{aligned}\n",
+    "$$\n",
     "\n",
     "where the scattering length densities are given with <mi>ρ</mi> and the coverage with <mi>ϕ</mi>. \n",
     "This means that when we investigate the `solvated_film` object, the scattering length density will be 3.09e-6 Å<sup>-2</sup>"

docs/src/tutorials/fitting/monolayer.ipynb

@@ -119,30 +119,11 @@
     "Each of these layers have some thickness that can be estimated by considering the size of the head and tail groups.\n",
     "The scattering length density (<mi>ρ</mi>) for the layers is then defined based on the layer thickness (<mi>d</mi>), the scattering length for the lipid head or tail molecule (<mi>b</mi>), the surface number density of the monolayer (defined by the area per molecule, APM) and the presence of solvent in the head or tail molecules (<mi>ϕ</mi> solvation), where the solvent has a known scattering length density (<mi>ρ</mi><sub>solvent</sub>),\n",
     "\n",
-    "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\">\n",
-    "  <mi>ρ</mi>\n",
-    "  <mo>=</mo>\n",
-    "  <mfrac>\n",
-    "    <mrow>\n",
-    "      <mi>b</mi>\n",
-    "    </mrow>\n",
-    "    <mrow>\n",
-    "      <mi>d</mi>\n",
-    "      <mi>APM</mi>\n",
-    "    </mrow>\n",
-    "  </mfrac>\n",
-    "  <mo>(</mo>\n",
-    "  <mn>1</mn>\n",
-    "  <mo>-</mo>\n",
-    "  <mi>ϕ</mi>\n",
-    "  <mo>)</mo>\n",
-    "  <mo>+</mo>\n",
-    "  <mi>ρ</mi>\n",
-    "  <msub>\n",
-    "    <mi>solvent</mi>\n",
-    "  </msub>\n",
-    "  <mi>ϕ</mi>\n",
-    "</math>\n",
+    "$$\n",
+    "\\begin{aligned}\n",
+    "\\rho = \\frac{b}{d\\mathrm{APM}}(1-\\phi) + \\rho_{\\mathrm{solvent}}\\phi\n",
+    "\\end{aligned}\n",
+    "$$\n",
     "\n",
     "This approach has two benefits: \n",
     "1. By constraining the area per molecule of the head and tail groups to be the same, the analysis can ensure that the number density of the two components is equal (i.e. for every head group there is a tail group), as would be expected given the chemical bonding.\n",