A=3i + 2j +k and Bz = -1i +2j +Bk. |A + B| =6. Find Bk

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Homework Help Overview

The problem involves two vectors, A and B, with specific components given. The task is to find the value of Bz such that the magnitude of the sum of the vectors equals 6.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the interpretation of the equation involving the vectors and their magnitudes. There is an exploration of how to manipulate the equation to find possible values for Bz, including questioning the correctness of derived values and the approach to solving the equation.

Discussion Status

The discussion includes attempts to clarify the equation and the values of Bz. Some participants have provided insights into how to set up the problem, while others express uncertainty about the correctness of their calculations. There is no explicit consensus on the final value of Bz, but some productive lines of reasoning have been shared.

Contextual Notes

Participants mention issues with online checks for correctness and the potential for multiple acceptable answers based on the problem's constraints. There is also a reference to the need for clearer formulation of the problem.

bmchenry
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Homework Statement



2 vectors are given by A=3i + 2j +k and Bz = -1i +2j +Bk. A + B =6

Homework Equations



Find the two possible vlaues of Bz

The Attempt at a Solution



6 = sqrt (4 + 20 +Bzsquared)

I get one number to equal -4.87 but when I solve for the other I get it wrong on the online check
 
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Is that the absolute value of A + B = 6?
 
yes it is the absolute value 6, I thought the answer would be to just take the positive 3.87 and subtract 1 from it but that was wrong online
 
Ok well in the equation you've come up with you wouldn't just have B2. When you add the vectors you would end up with a term (1+B)2. What values can B take to make everything under square root add up to 36?
 
Did that and for one answer I got -4.87 which when you put it in the () and square it you get 36 or close enough that the online problem accepted the answer, I assumed that for the other number I just needed to take 3.87 and subtract the 1 which left me with 2.87, however when I plug that in it says it is incorrect, where is my mistake?
 
Can you formulate the problem in a better way? For example you know that:

(B+1)^2 = 12

How would you solve that for B.
 
Never mind but thanks, I figured it out the answer is 3, but I need help bisecting a vector can you help?
 
3? I would not have thought it would be, but the online thing might be accepting answers within certain ranges. It would be best to post a new thread to receive the maximum attention.
 

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