Final answer:
The expression tan(2α)cos2α is defined for all values of α that are not odd multiples of π/2.
Step-by-step explanation:
To find all values of α for which the expression tan(2α)cos2α is defined, we need to consider the domains of the trigonometric functions involved.
First, we know that tan(2α) is defined for all values of α that are not odd multiples of π/2. This means that α cannot be equal to (2n + 1)π/4, where n is an integer.
Second, cos2α is defined for all values of α. Therefore, the expression tan(2α)cos2α is defined for all values of α that are not odd multiples of π/2.