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

  • Thread starter DavidLiew
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In summary, the formula for finding ||2w-v|| is ||w-v|| = ||w|| - 2||v||cos(theta), where theta is the angle between vector w and vector v. To find the value of <v,w>, use the formula <v,w> = ||v|| * ||w|| * cos(theta), where theta is the angle between vector v and vector w. In this case, the value of <v,w> is -3. No, the Pythagorean theorem only applies to right triangles, while ||2w-v|| is the magnitude of a vector. The units for ||2w-v|| are the same as the units for ||v|| and ||w||, since ||2
  • #1
DavidLiew
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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:
 
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  • #2
Finally I find it is equal to [tex]\sqrt{212}[/tex]. Am I right?
 
  • #3
DavidLiew said:
Finally I find it is equal to [tex]\sqrt{212}[/tex]. Am I right?

I got the same answer.
 

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

1. What is the formula for finding ||2w-v||?

The formula for finding ||2w-v|| is ||w-v|| = ||w|| - 2||v||cos(theta), where theta is the angle between vector w and vector v.

2. How do I find the value of when given ||v|| and ||w||?

To find the value of , use the formula = ||v|| * ||w|| * cos(theta), where theta is the angle between vector v and vector w. In this case, the value of is -3.

3. Can I use the Pythagorean theorem to find ||2w-v||?

No, the Pythagorean theorem only applies to right triangles, while ||2w-v|| is the magnitude of a vector.

4. What are the units for ||2w-v||?

The units for ||2w-v|| are the same as the units for ||v|| and ||w||, since ||2w-v|| is a scalar quantity. In this case, the units would be the same as the units for ||v|| and ||w||, such as meters or seconds.

5. Is ||2w-v|| equal to ||v-w||?

No, ||2w-v|| is not equal to ||v-w||. The order of subtraction matters when finding the magnitude of a vector, so ||2w-v|| is not equivalent to ||v-w||.

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