Finding the value of x in vector equations

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Katherine Fanning
Katherine Fanning el 23 de Mayo de 2020
Respondida: Walter Roberson el 23 de Mayo de 2020
I have a basic trig background and am struggling with this particular equation:
(x+2)i+(2y-1)j=yi+3xj
The objective of the equation is find the value of x. How do I go about that?
  2 comentarios
Walter Roberson
Walter Roberson el 23 de Mayo de 2020
Are i and j both real-valued unknowns?
Are i and j both names for the same sqrt(-1) ?
Is i sqrt(-1) and j is sqrt(-1) "in a different direction" ?
Is i a unit vector on the y axis and j is a unit vector on the z axis?
Is i a unit vector on the x axis and j is a unit vector on the y axis?
Katherine Fanning
Katherine Fanning el 23 de Mayo de 2020
i is a unit vector on the x axis, j is a unit vector on the y axis.

Iniciar sesión para comentar.

Respuestas (1)

Walter Roberson
Walter Roberson el 23 de Mayo de 2020
(-8*x-4)*i + (y+9)j = 9*y*i -7*x*j
i and j are independent so you can separate the variables
(-8*x-4)*i = 9*y*i
(y+9)*j = -7*x*j
Remove the units
-8*x-4 = 9*y
y+9 = -7*x
isolate y. Second equation is easier
y+9 = -7*x -> y = -7*x - 9
Substitute into the other equation
-8*x - 4 = 9*(-7*x - 9)
Expand
-8*x - 4 = -63*x - 81
isolate x
-8*x + 63*x = -81 + 4
55 * x = -77
x = -77/55

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