Original
Would this theorem hold if we were working on a closed interval
{{MATH_183}}, but a function is not continuous on {{MATH_184}}?
{{CMD_185}}
{{CMD_186}}
{{CMD_187}}yes{{CMD_188}}
{{CMD_189}}no{{CMD_190}}
{{CMD_191}}
{{CMD_192}}
Consider a function {{MATH_193}} on a closed interval {{MATH_194}}, defined
by {{MATH_195}} for {{MATH_196}} and {{MATH_197}} . Does this
function achieve its maximum or minimum?
{{CMD_198}}
{{CMD_199}}
{{CMD_200}}
Assume that a function {{MATH_201}} is continuous on a closed interval
{{MATH_202}}. By the Extreme Value Theorem, {{MATH_203}} attains both global
extremums on the interval {{MATH_204}}. How can we locate these global
extrema? We have seen that they can occur at the end points or in the
open interval {{MATH_205}}. If a global extremum occurs at a point {{MATH_206}} in
the open interval {{MATH_207}}, then {{MATH_208}} has a local extremum at {{MATH_209}}. That
means that {{MATH_210}} has a critical point at {{MATH_211}}. So, the global extrema of
a function {{MATH_212}} occur either at the end points, {{MATH_213}} or {{MATH_214}}, or at
critical points. If we want to locate the global extrema, we have to
evaluate the function at the end points and at critical points, and
compare the values.