Answer:
B) All real numbers except 0 and integer multiples of 8π∕5
Step-by-step explanation:
Cotangent function:
The cotangent function is given by:
[tex]y = \cot{ax} = \frac{\cos{ax}}{\sin{ax}}[/tex]
Domain:
All real values except those at which:
[tex]\sin{ax} = 0[/tex]
The sine is 0 for 0 and all integer multiples of [tex]\frac{1}{a}[/tex]
In this question:
[tex]a = \frac{5}{8}[/tex], so the values outside the domain are 0 and the integer multiples of [tex]\frac{8}{5}[/tex]. Then the correct answer is given by option b.