Matrices and Vectors
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Pre-Calculus › Matrices and Vectors
Find the component form of the vector with
initial point
and
terminal point .
Explanation
To find the vector in component form given the initial and terminal points, simply subtract the initial point from the terminal point.
Find , then find its magnitude.
and
are both vectors.
Explanation
In vector addition, you simply add each component of the vectors to each other.
x component: .
y component: .
z component: .
The new vector is
.
To find the magnitude we use the formula,
Thus its magnitude is 5.
Find the dot product of the two vectors
and
.
Explanation
To find the dot product of two vectors,
find the product of the x-components,
find the product of the y-components,
and then find the sum.
Find the dot product of the two vectors
and
.
Explanation
To find the dot product of two vectors,
find the product of the x-components,
find the product of the y-components,
and then find the sum.
Find the parametric equations for a line parallel to and passing through the point (4, -3).
x = 4 - 7t
y = -3 + 3.5t
x = -7 + 4t
y = 3.5 - 3t
x = -3 + 3.5t
y = 4 - 7t
x = -3 - 3.5t
y = 4 + 7t
Explanation
A line through a point (x1,y1) that is parallel to the vector = (a1, a2) has the following parametric equations, where t is any real number.
Using the given vector and point, we get the following:
x = 4 - 7t
y = -3 + 3.5t
Each value of t creates a distinct (x, y) ordered pair. You can think of these points as representing positions of an object, and of t as representing time in seconds. Evaluating the parametric equations for a value of t gives us the coordinates of the position of the object after t seconds have passed.
Write a vector equation describing the line passing through P1 (1, 4) and parallel to the vector = (3, 4).
Explanation
First, draw the vector = (3, 4); this is represented in red below. Then, plot the point P1 (1, 4), and draw a line
(represented in blue) through it that is parallel to the vector
.

We must find the equation of line . For any point P2 (x, y) on
,
. Since
is on line
and is parallel to
,
for some value of t. By substitution, we have
. Therefore, the equation
is a vector equation describing all of the points (x, y) on line
parallel to
through P1 (1, 4).
Find the parametric equations for a line parallel to and passing through the point (0, 5).
x = 5t
y = 3 + 2t
x = 3 + 2t
y = 5t
x = 3
y = 2 + 5t
x = 3t
y = 5 + 2t
Explanation
A line through a point (x1,y1) that is parallel to the vector = (a1, a2) has the following parametric equations, where t is any real number.
Using the given vector and point, we get the following:
x = 3t
y = 5 + 2t
Each value of t creates a distinct (x, y) ordered pair. You can think of these points as representing positions of an object, and of t as representing time in seconds. Evaluating the parametric equations for a value of t gives us the coordinates of the position of the object after t seconds have passed.
Write an equation in slope-intercept form of the line with the given parametric equations:
Explanation
Start by solving each parametric equation for t:
Next, write an equation involving the expressions for t; since both are equal to t, we can set them equal to one another:
Multiply both sides by the LCD, 6:
Get y by itself to represent this as an equation in slope-intercept (y = mx + b) form:
Write the parametric equation for the line y = -3x +1.5
x = -3t +1.5
y = -3t +1.5
x = t
y = 1.5t - 3
x = t
y = -3t +1.5
x = -3t +1.5
y = t
Explanation
In the equation y = -3x +1.5, x is the independent variable and y is the dependent variable. In a parametric equation, t is the independent variable, and x and y are both dependent variables.
Start by setting the independent variables x and t equal to one another, and then you can write two parametric equations in terms of t:
x = t
y = -3t +1.5
Find the parametric equations for a line parallel to and passing through the point (4, -3).
x = 4 - 7t
y = -3 + 3.5t
x = -7 + 4t
y = 3.5 - 3t
x = -3 + 3.5t
y = 4 - 7t
x = -3 - 3.5t
y = 4 + 7t
Explanation
A line through a point (x1,y1) that is parallel to the vector = (a1, a2) has the following parametric equations, where t is any real number.
Using the given vector and point, we get the following:
x = 4 - 7t
y = -3 + 3.5t
Each value of t creates a distinct (x, y) ordered pair. You can think of these points as representing positions of an object, and of t as representing time in seconds. Evaluating the parametric equations for a value of t gives us the coordinates of the position of the object after t seconds have passed.