Answer:
csc (0°) and sec (90°) are not defined.
Step-by-step explanation:
Given the options wehave to select the option which is undefinesd
First option: sec 45°
[tex]sec45^{\circ}=\frac{1}{cos(45^{\circ})}=\frac{1}{\frac{1}{\sqrt2}}=\sqrt2[/tex]
which is defined
Second option: csc(0°)
[tex]csc(0^{\circ})=\frac{1}{sin0}=\frac{1}{0}=\infty[/tex]
which is not defined
Third option: sec(90°)
[tex]sec(90^{\circ})=\frac{1}{cos(90)}=\frac{1}{0}=\infty[/tex]
which is not defined.
Hence, option 2 and 3 are not defined.
