Vector Cross Product. Let vectors A=(1,0,-3), B =(-2,5,1), and C =(3,1,1).Calculate the following, expressing your answers as ordered triples

Khaleesi Herbert

Khaleesi Herbert

Answered question

2021-09-20

Vector Cross Product
Let vectors A=(1,0,-3), B =(-2,5,1), and C =(3,1,1). Calculate the following, expressing your answers as ordered triples (three comma-separated numbers).
(C) (2B)(3C)
(D) (B)(C)
(E) overA(overB×overC)
(F)If v1  and  v2 are perpendicular, |v1×v2|
(G) If v1  and  v2 are parallel, |v1×v2|

Answer & Explanation

Viktor Wiley

Viktor Wiley

Skilled2021-09-21Added 84 answers

Calculation:
alenahelenash

alenahelenash

Expert2023-06-19Added 556 answers

(C) To calculate (2B)(3C), we first find the cross product of B and C:
B×C=|i^j^k^251311|=(51)i^(63)j^(2+15)k^=6i^3j^17k^.
Multiplying this result by 2 and 3 respectively, we have:
(2B)(3C)=2(6i^3j^17k^)·3(3i^+j^+k^)=(12i^6j^34k^)·(9i^+3j^+3k^).
Expanding the dot product, we get:
(12i^6j^34k^)·(9i^+3j^+3k^)=(12)(9)+(6)(3)+(34)(3)=(108,18,102).
(D) To calculate (B)(C), we simply take the dot product of B and C:
(B)(C)=(2i^+5j^+1k^)·(3i^+1j^+1k^)=(2)(3)+(5)(1)+(1)(1)=3.
(E) To calculate A(B×C), we substitute the cross product of B and C into the equation:
A(B×C)=(1i^+0j^3k^)·(6i^3j^17k^)=(1)(6)+(0)(3)+(3)(17)=51.
(F) If v1 and v2 are perpendicular, the magnitude of their cross product is given by |v1×v2|.
star233

star233

Skilled2023-06-19Added 403 answers

Step 1:
(C) (2B)(3C):
Given vectors B=(2,5,1) and C=(3,1,1), we can calculate the cross product as follows:
2B=2(2,5,1)=(4,10,2)
3C=3(3,1,1)=(9,3,3)
Now, we'll calculate the cross product of 2B and 3C:
(2B)(3C)=(4,10,2)×(9,3,3)
Using the cross product formula, we can evaluate this expression:
(2B)(3C)=(10·32·3,2·9(4)·3,(4)·310·9)
(2B)(3C)=(24,30,102)
Therefore, the answer to (C) is (24,30,102).
Step 2:
(D) (B)(C):
Given vectors B=(2,5,1) and C=(3,1,1), we'll calculate the dot product as follows:
(B)(C)=(2,5,1)·(3,1,1)
Using the dot product formula, we get:
(B)(C)=2·3+5·1+1·1
(B)(C)=6+5+1
(B)(C)=0
Therefore, the answer to (D) is 0.
Step 3:
(E) A(B×C):
Given vectors A=(1,0,3), B=(2,5,1), and C=(3,1,1), we'll calculate the cross product as follows:
B×C=(2,5,1)×(3,1,1)
Using the cross product formula, we can evaluate this expression:
B×C=(5·11·1,1·3(2)·1,(2)·15·3)
B×C=(4,5,17)
Now, we'll calculate A(B×C):
A(B×C)=(1,0,3)·(4,5,17)
Using the dot product formula, we get:
A(B×C)=1·4+0·5+(3)·(17)
A(B×C)=4+0+51
A(B×C)=55
Therefore, the answer to (E) is 55.
Step 4:
(F) If v1 and v2 are perpendicular, |v1×v2|:
If v1 and v2 are perpendicular, the magnitude of their cross product can be calculated using the formula:
|v1×v2|=|v1||v2|sin(θ)
Since v1 and v2 are perpendicular, sin(θ)=1, and the formula simplifies to:
|v1×v2|=|v1||v2|×1
|v1×v2|=|v1||v2|
Therefore, the magnitude of the cross product of v1 and v2 is equal to the product of their magnitudes.
Step 5:
(G) If v1 and v2 are parallel, |v1×v2|:
If v1 and v2 are parallel, the cross product of two parallel vectors is zero. Therefore:
|v1×v2|=0
Therefore, the magnitude of the cross product of v1 and v2 is zero if the vectors are parallel.
karton

karton

Expert2023-06-19Added 613 answers

Solution:
(C) To find (2B)(3C), we first need to calculate 2B and 3C separately:
2B=2(2,5,1)=(4,10,2)
3C=3(3,1,1)=(9,3,3)
Now, we can multiply these vectors:
(2B)(3C)=(4,10,2)×(9,3,3)
Using the cross product formula, the resulting vector is:
(2B)(3C)=|i^j^k^4102933|=(60,6,66)
Therefore, (2B)(3C)=(60,6,66)
(D) To calculate (B)(C), we can simply use the dot product formula:
(B)(C)=(2,5,1)·(3,1,1)=(2)(3)+(5)(1)+(1)(1)=6+5+1=0
Thus, (B)(C)=0
(E) To find A(B×C), we first need to calculate B×C:
B×C=|i^j^k^251311|=(4,5,13)
Now, we can multiply this result with A:
A(B×C)=(1,0,3)×(4,5,13)
Using the cross product formula, the resulting vector is:
A(B×C)=|i^j^k^1034513|=(15,5,5)
Hence, A(B×C)=(15,5,5)
(F) If v1 and v2 are perpendicular, then the magnitude of their cross product can be calculated as:
|v1×v2|=|v1|·|v2|
Thus, if v1 and v2 are perpendicular, |v1×v2|=|v1|·|v2|
(G) If v1 and v2 are parallel, then their cross product will be zero, i.e., v1×v2=0.
Thus, if v1 and v2 are parallel, |v1×v2|=|0|=0

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