Update theory.md

experiment/theory.md

@@ -18,7 +18,7 @@ From the frequency plot, the user can identify the natural frequency of the beam
 frequency corresponding to which peak in the G-plot. The user may compare the frequency obtained
 through this experiment with the theoretical frequency given below (Paz, 2004). 
 
-<img src="images/th3.png" height="70px">
+<img src="images/th3.png" height="80px">
 
 Where E denotes the Young's modulus of elasticity of the beam, ρ the material density and L<sub>half</sub> the half length of the beam. The user may compute the first ten frequencies by substituting n = 1, 2..., 10 and conclude as to which frequency is identified.