corrected markdown syntax

README.md

@@ -4,9 +4,9 @@ Demo of uploading assignment
 
 ## Solution to Gold Chain nonlinear spring constants
 
-!(Gold chain TEM image)[au_chain.jpg]
+![Gold chain TEM image](au_chain.jpg)
 
-!(Gold chain model (artist rendition))[Auchain_model.png]
+![Gold chain model (artist rendition)](Auchain_model.png)
 
 # Homework #3 plots of Gold chain F vs dx and Lennard-Jones Potential
 
@@ -56,6 +56,6 @@ This script in included as `gold_chain_script.m`
 
 Output is two plots, 'potential_energy.png' and 'force_vs_dx.png'
 
-!(Lennard-Jones potential energy for no applied force)[potential_energy.png]
+![Lennard-Jones potential energy for no applied force](potential_energy.png)
 
-!(Force vs displacement for gold chain)[force_vs_dx.png]
+![Force vs displacement for gold chain](force_vs_dx.png)