The answer is for the problem shown above is:
secx=1/cosx
The explanation is shown below:
1. To solve this problem you must apply the following proccedure:
2. You have to verify if secx sinx=tanx, so, you have:
3. You know that secx=1/cosx, and tanx=sinx/cosx, therefore:
(secx)(sinx)
(1/cosx)(sinx)
sinx/cosx
tanx
