E=mc2
E=mc
2
E=mc
2
E=mc
2
E=mc
2
E=mc
2
logx
log
x
log
x
log
x
log
x
logex2
log
e
x
2
log
e
x
2
log
e
x
2
log
e
x
2
Phythagoras theorem
c
2
=a
2
+b
2