Show:
Straight lines
Parabolas
Equations
Methods
Examples
100
What is the difference between proportional and linear functions.
A proportional function always passes throught the origin.
100
How do we calculate the x-coordinate of the vertex?
The x-coordinate of the vertex is -b/2a
100
Which is the equation of a straight line of slope 2 that passes through the point (1,3)
y = 2x + 1
100
How many points do we need to represent a proportional function?
One point
100
1 foot = 304,8 mm. Write the equation that associates feet (x) to cm (y).
y = 30,48x
200
When are parallel a proportional and a linear function?
When they have the same slope.
200
How do we know from the equation of a parabola whether it has a maximum or a minimum?
If a is positive the parabola has a minimum. Otherwise, it has a maximum.
200
Which is the equation of a straight line of y-intercept 2 that passes through the point (1,3)
y = x + 2
200
How can we obtain the common point of two secant straight lines?
We solve the system of the equations of the functions.
200
Write the equation that associates centigrade degrees (x) and Kelvin degrees (y)
y = x - 273,3
300
Give a real life example of a proportional function
The teacher will say if the answer is correct
300
When is a parabola an even function?
When the vertex belongs to the y-axis.
300
Which are the slope and the y-intercept of the function: 2y - 1 = x - 1
m = 1/2, n = 0
300
Looking at their equations, how do we know that 2 straight lines don't have a common point?
Their slopes are equal.
300
The lenght (y) of a spring is 12 cm when it is streched with a force (x) of 20N and 10 cm when the force is of 10N. Calculate the equation that associates lenght and force.
y = x/5 + 8
400
Which of these possibilities is untrue and why? a) A linear function passes through the first, second and third quadrants. b) A linear function passes through the first and second quadrants. c) A proportional function passes through the second and third quadrants.
When the function is constant. (e.g. y=3)
400
How is the equation of a parabola that passes through the origin?
c = 0
400
Write the equation of the straight line that passes through the points (1,3) and (4,7)
y = 4x/3 + 5/3
400
How do we obtain the intersections of a parabola with the x-axis?
We solve the equation of the parabola, replacing y by zero.
400
Which is the formula that associates Farenheit degrees with Celsius degrees knowing that water freezes at 32ºF and boils at 212ºF
F = 1,8C + 32 or F = 9x/5 + 32
500
Give a real life example of a linear function
The teacher will say if the answer is correct
500
How is the equation of a parabola whose vertex is in the origin?
b and c = 0
500
Write the equation of a straight line parallel to the proportional line that passes through the point (-3,-4) and intersects the x-axis in x = 4.
y = 4x/3 - 16/3
500
How can we obtain the coordinates of the intersection of the diagonals of a parallelogram?
We solve the system of the equations of the straight lines that contain the diagonals.
500
Which is the equation that associates time (x) and distance travelled (y) by a bomb that falls from an airplane at 1000 m?
x = 1000 - 9,8te2