Given vectors A (2,-1,5), B (4,3,-2) & C (5,4,0), find:?
1 answer:
A) 4a - 3b + 2c
4(2, -1, 5) - 3(4, 3 , -2) + 2(5, 4, 0) = (8, -4, 20) - (12, 9, - 6) + (10, 8, 0) =
= (8 - 12 + 10 , -4 - 9 + 8 , 20 + 6 + 0) = (6, - 5, 26)
Answer: (6, - 5, 26)
b) magnitude of vector b
c) vector of length 7 parallel to vector c
=> m(5,4,0) = (5m,4m,0)
=>
=> m = 7 / √41 ≈ 1.093
=> 1.093 (5, 4, 0) = (5.465 , 4.372, 0)
Answer: (5.465 , 4.372 , 0)
4(2, -1, 5) - 3(4, 3 , -2) + 2(5, 4, 0) = (8, -4, 20) - (12, 9, - 6) + (10, 8, 0) =
= (8 - 12 + 10 , -4 - 9 + 8 , 20 + 6 + 0) = (6, - 5, 26)
Answer: (6, - 5, 26)
b) magnitude of vector b
c) vector of length 7 parallel to vector c
=> m(5,4,0) = (5m,4m,0)
=>
=> m = 7 / √41 ≈ 1.093
=> 1.093 (5, 4, 0) = (5.465 , 4.372, 0)
Answer: (5.465 , 4.372 , 0)
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Answer:
x = 6, 9
Step 1:
To solve this equation, we need to subtract 3 from both sides like this:
Step 2:
We square both sides (multiply using FOIL) to get rid of the radical.
If you did not understand how these were done, here is an example:
(x + 1)(x + 2)
First terms: x * x = <u><em>x^2</em></u>
Outer terms: x * 2 = 2x
Inner terms: 1 * x = x
2x - x = <u><em>x</em></u>
Last terms: 1 * 2 =<em> </em><u><em>2</em></u>
x^2 + x + 2
Step 3:
Solve for x:
9x - 45 = x^2 - 6x + 9
x^2 - 6x + 9 (+45) = 9x - 45 (+45)
x^2 - 6x + 54 (-9x) = 9x (-9x)
x^2 - 15x + 54 = 0
Factor:
(x^2 - 6x) + (- 9x + 54)
x(x - 6) - 9(x - 6)
Factor out (x - 6):
(x - 6)(x - 9) = 0
x - 6 = 0; 6 - 6 = 0
x - 9 = 0; 9 - 9 = 0
Our anwer: x = 6, 9