Textbook - Error in cofunction identity - Precalculus Glenco Mc Graw Hill.

[jddoxtator]

Just sanity checking this.
The last cosecant cofunction identity should be equal to "r/x" not "r/y" correct?
The current statement would be a secant cofunction identity would it not?

 

[Dr.Peterson]

View attachment 39039
Just sanity checking this.
The last cosecant cofunction identity should be equal to "r/x" not "r/y" correct?
The current statement would be a secant cofunction identity would it not?

You're right. They must have had cosecant stuck in their minds, because $\frac{r}{y}$ is $\csc(\alpha)$, not $\sec(\alpha)=\csc(\beta)$.

 

[jddoxtator]

You're right. They must have had cosecant stuck in their minds, because $\frac{r}{y}$ is $\csc(\alpha)$, not $\sec(\alpha)=\csc(\beta)$.

Good to know I'm not crazy then.