Let f(x) and g(x) achieve their maximum value at x
1
and x
2
respectively.
h(x)=f(x)−g(x)
h(x
)=f(x
)−g(x
)≥0
)≤0
⇒h(c)=0 where c∈[0,1] ⇒f(c)=g(c)
