Need M3 help! Is the book wrong?

[eliza345]

In chapter 3 of the M3 edexcel book, pg 46, example 6.

In part B of the question, shouldn't X=4R?

 

[Ayesha B]

I can't help because I don't do M3, but take comfort in the fact that these books do make mistakes sometimes.

 

[saifulahmed49]

In chapter 3 of the M3 edexcel book, pg 46, example 6.

In part B of the question, shouldn't X=4R?

did you get root 11/12 gR?