# Which of these relations are functions of x on R

#### Erenjaeger

Mentor note: moved to homework section

y = sin(x)
y = cos(x)
y = tan(x)
y = csc(x)
y = sec(x)
y = cot(x)

(a) 0 (b) 4 (c) 6 (d) 2
I thought it was (c) because i graphed all the trig functions and they passed the vertical line test but the answer sheet is saying (d) 2

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#### pwsnafu

Science Advisor
"on R" is referring to the domain of function being all real numbers. Only sine and cosine satisfy this.

#### Erenjaeger

"on R" is referring to the domain of function being all real numbers. Only sine and cosine satisfy this.
oh true, thats where i was confused i think then, so is that because the others have vertical asymptotes ?

#### mathwonk

Science Advisor
Homework Helper
no, it is because they are not defined at the x coordinate of the vertical asymptote. but i think that is what you meant.

#### Erenjaeger

no, it is because they are not defined at the x coordinate of the vertical asymptote. but i think that is what you meant.
yeah thats what i was meaning, thanks

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