In[]:=
f[x_]:=
x
​​x0=0​​x1=5​​M=2*Pi*Integratef[x]*
1+f'[x]^2
,{x,x0,x1}//Expand​​%//N
Out[]=
0
Out[]=
5
Out[]=
-
π
6
+
7
21
π
2
Out[]=
49.8645