why do they multiply the domain by 2 (2 Viewers)

[anonymoushehe]

this is probably such a dumb a question but I’m so confused; what’s the point of letting a another variable equal to the compound angle and when you do why do they multiply the domain ??

 

[liamkk112]

this is probably such a dumb a question but I’m so confused; what’s the point of letting a another variable equal to the compound angle and when you do why do they multiply the domain ??

they multiple the domain so they know all of the range of the possible values of 2x, it’s just helpful so you don’t miss any possible angles. idk why they did a sub though