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Example Questions
Example Question #1 : Express A Vector In Component Form
Write this vector in component form:
In order to find the horizontal component, set up an equation involving cosine with 7 as the hypotenuse, since the side in the implied triangle that represents the horizontal component is adjacent to the 22-degree angle:
First, find the cosine of 22, then multiply by 7
To find the vertical component, set up an equation involving sine, since the side in the implied triangle that represents the vertical component is opposite the 22-degree angle:
First, find the sine of 22, then multiply by 7
We are almost done, but we need to make a small adjustment. The picture indicates that the vector points up and to the left, so the horizontal component, 6.49, should be negative:
Example Question #31 : Algebraic Vectors And Parametric Equations
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).
Example Question #1 : Parametric Equations
True or false: A line through P1 (x1, y1) that is parallel to the vector is defined by the set of points such that for some real number t. Therefore, .
False
True
True
This is true. The independent variable in this equation is called a parameter.
Example Question #32 : Algebraic Vectors And Parametric Equations
Find the parametric equations for a line parallel to and passing through the point (0, 5).
x = 3t
y = 5 + 2t
x = 3
y = 2 + 5t
x = 5t
y = 3 + 2t
x = 3 + 2t
y = 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.
Example Question #41 : Algebraic Vectors And Parametric Equations
Find the parametric equations for a line parallel to and passing through the point (4, -3).
x = -3 + 3.5t
y = 4 - 7t
x = -7 + 4t
y = 3.5 - 3t
x = -3 - 3.5t
y = 4 + 7t
x = 4 - 7t
y = -3 + 3.5t
x = 4 - 7t
y = -3 + 3.5t
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.
Example Question #3 : Parametric Equations
Write the parametric equation for the line y = -3x +1.5
x = -3t +1.5
y = -3t +1.5
x = t
y = -3t +1.5
x = t
y = 1.5t - 3
x = -3t +1.5
y = t
x = t
y = -3t +1.5
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
Example Question #1361 : Pre Calculus
Write the parametric equation for the line y = 5x - 3.
x = t
y = 5t - 3
x = t
y = t
x = 5t - 3
y = t
x = 5t - 3
y = 5t - 3
x = t
y = 5t - 3
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
Example Question #4 : 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, 4:
Get y by itself to represent this as an equation in slope-intercept (y = mx + b) form:
Example Question #5 : 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:
Example Question #6 : Parametric Equations
A football punter kicks a ball with an initial velocity of 40 ft/s at an angle of 29o to the horizontal. After 0.5 seconds, how far has the ball travelled horizontally and vertically?
To solve this problem, we need to know that the path of a projectile can be described with the following equations:
In these equations, t is time and g is the acceleration due to gravity.
First, you need to write the position of the ball as a pair of parametric equations that define the path of the ball at anytime, t, in seconds:
As you set up the equation for y, use the value g = -32.
Finally, find x and y when t = .05:
Use a calculator to solve, making sure you are in degree mode:
This means that after 0.5 seconds, the ball has travelled 17.5 feet horizontally and 5.7 feet vertically.
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