Find ||2w-v|| from <v,w>=-3, ||v||=2, ||w||=7

[DavidLiew]

How to find a ||2w-v||,by giving <v,w> = -3, ||v||=2 and ||w||= 7.

Actually I find that it was undefined, I not sure its correct or not, so I need yours to help me thanks.:shy:

 

[DavidLiew]

Finally I find it is equal to $$\sqrt{212}$$. Am I right?

 

[jbunniii]

Finally I find it is equal to $$\sqrt{212}$$. Am I right?

I got the same answer.