### Home > CCA2 > Chapter 7 > Lesson 7.2.3 > Problem 7-147

Ceirin’s teacher promised a quiz for the next day, so Ceirin called Adel to review what they had done in class.*“Suppose I have y = sin2x,”*said Ceirin,*“what will its graph look like?”**“It will be horizontally compressed by a factor of 2,”*replied Adel,*“so the period must be π.”**“Okay, now let’s say I want to shift it one unit to the right. Do I just subtract 1 from x, like always?”**“I think so,”*said Adel,*“but let’s check on the graphing calculator.”*They proceeded to check on their calculators. After a few moments they both spoke at the same time.*“*Rats,” said Ceirin,*“it isn’t right.”**“Cool,”*said Adel,*“it works.”*When they arrived at school the next morning, they compared the equations they had put in their graphing calculators while they talked on the phone. One had

*y*= sin 2*x*− 1, while the other had*y*= sin2(*x*− 1).Which equation was correct? Did they both subtract 1 from

*x*? Explain. Describe the rule for shifting a graph one unit to the right in a way that avoids this confusion. Homework Help ✎

If you want to subtract 1 from *x* before multiplying, are parenthesis necessary?

The equation *y* = sin2(*x* − 1) is correct. To shift the graph one unit to the right, subtract 1 from *x* before multiplying by anything.