If f be a function defined on an interval I and there exists a point “a” in I such that f(a) ≥ f(x) for all x ∈ I , then
The number f(a) is called the global maximum of f(x) in I
Global maximum occurs at x = a
To answer this question we have to understand the concept of global maxima and the difference between global maxima and local maxima. Unlike local maxima where a point has higher output than other local points (neighborhood) global maxima is always discussed in an interval. If there is a point in the interval which has the higher output compared to all other values in that interval then that point is said to be a global maxima and the value or output is called global maximum.