Correct update of pressure (#298)

* Correct update of pressure

As pointed out by Nachiket Gokhale

* Pin jupyterbook

* Fix another typo noted by Nachiket Gokhale

Author: jorgensd

chapter2/navierstokes.md

@@ -68,11 +68,11 @@ As mentioned in the note in [Linear elasticity implementation](./linearelasticit
 $w_i=\sum_{j}\left(u_j\frac{\partial}{\partial x_j}\right)u_i = \sum_j u_j\frac{\partial u_i}{\partial x_j}$. 
 This term can be  implemented in  FEniCSx as either 
 `grad(u)*u`, since this expression becomes $\sum_j\frac{\partial u_i}{\partial x_j}u_j$, or as `dot(u, nabla_grad(u))` since this 
-expression becomes $\sum_i u_i\frac{\partial u_j}{x_i}$. We will use the notation `dot(u, nabla_grad(u))` below since it corresponds more closely to the standard notation $u\cdot \nabla u$.
+expression becomes $\sum_i u_i\frac{\partial u_j}{\partial x_i}$. We will use the notation `dot(u, nabla_grad(u))` below since it corresponds more closely to the standard notation $u\cdot \nabla u$.
 ```
 
 We now move on to the second step in  our splitting scheme for the incompressible Navier-Stokes equations. In the first step, we computed the *tentative velocity* $u^*$ based on the pressure from the previous time step. 
-We may now use the computed tentative velocity to compute the new pressure $p^n$:
+We may now use the computed tentative velocity to compute the new pressure $p^{n+1}$:
 ```{math}
 :label: ipcs-two
     \langle \nabla p^{n+1}, \nabla q \rangle = \langle \nabla p^n, \nabla q\rangle - \frac{\rho}{\Delta t}\langle \nabla \cdot u^*, q\rangle.

pyproject.toml

@@ -6,7 +6,7 @@ build-backend = "setuptools.build_meta"
 name = "DOLFINx_Tutorial"
 version = "0.11.0.dev0"
 dependencies = [
-    "jupyter-book<2.0.0",
+    "jupyter-book<2.0",
     "meshio",
     "h5py",
     "seaborn",