Chapter 5 Straight Line Graphs - Year 1 Flashcards
What is an integer?
A whole number
How do you determine where a line crosses the y axis?
Put x equal to 0
How do you determine where a line crosses the x axis?
Put y equal to 0
How do you work out the gradient of a line?
(y1-y2) ÷ (x1-x2)
If you are given the gradient and 2 points with 1 point an unknown. What do you do?
Use (y1-y2) ÷ (x1-x2) = m
Substitute as you know m and solve
If you are given 2 points on a line how do you calculate the equation of the line?
Expand on your answer.
Calculate the gradient using (y1-y2) ÷ (x1-x2)
Use y1-y2=m(x1-x2)
Substitute and solve
If it wants it in the form ax+by+c=0 and you gradient is a fraction, instead of expanding the brackets multiply by the denominator of the fraction
What do we know about parral lines?
Their gradients are the same
What do we know about perpendicular lines?
There gradients have a product of -1
(Negative reciprocal)
How do you find the length of a line when given 2 points?
You do:
y1-y2=a
x1-x2=b
sqr(a+b)= the answer
What do you need to be careful about when working out the area of a triangle when you are given 3 co-ordinate points?
Sometimes the base may be vertical meaning that the perpendicular height will be worked out using the x co-ordinate
Do linear models have to be exactly linear?
No
What is important to remember when stating the equation of a linear model?
Use the letters that they give you
Eg H=5t+7
Modelling
How so you prove that 3 points are on a straight line?
You prove that they create the same gradient
How do you prove 2 lines are perpendicular?
Their gradients have a product of -1
