Pre-Calculus › Algebraic Vectors and Parametric Equations
Write an equation in slope-intercept form of the line with the given parametric equations:
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:
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
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 a vector equation describing the line passing through P1 (1, 4) and parallel to the vector = (3, 4).
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 (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
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.
Find the component form of the vector with
initial point
and
terminal point .
To find the vector in component form given the initial and terminal points, simply subtract the initial point from the terminal point.
Write the parametric equation for the line y = 5x - 3.
x = 5t - 3
y = t
x = t
y = 5t - 3
x = 5t - 3
y = 5t - 3
x = t
y = t
In the equation y = 5x - 3, 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 = 5t - 3
Write this vector in component form:
To figure out the horizontal component, set up an equation involving cosine, since that side of the implied triangle is adjacent to the 48-degree angle:
To solve for x, first find the cosine of 48, then multiply by 11:
To figure out the vertical component, set up an equation involving sine, since that side of the implied triangle is opposite the 48-degree angle:
to solve for y, just like x, first find the sine of 48, then multiply by 11:
Putting this in component form results in the vector
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
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.
Find , then find its magnitude.
and
are both vectors.
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.
Write an equation in slope-intercept form of the line with the given parametric equations:
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: