Definitions
A Reminder
- A Cartesian graph is a graph drawn on a number plane with two perpendicular axes, the x-axis and the y-axis.
- Coordinates are the ordered pairs that locate points on a graph. The first number is the distance along the x-axis (horizontal) and the second number is the distance along the y-axis (vertical).
- Each point is located by an ordered pair. e.g. (x, y), (3, 4)
- The origin is the point where the two axes intersect. The origin has coordinates of (0, 0).
- The intercepts of a graph are the points where the graph cuts the x-axis and y-axis.
Gradient
The gradient of a straight line is a measure of its slope.
The gradient, m is defined as:
Gradients can be given as integers, fractions or decimals.
Types of gradient
A line sloping upwards from left to right has a positive gradient.
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m is positive
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A line sloping downwards from left to right has a negative gradient.
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m is negative
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Parallel lines have the same gradient.
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m1 = m2
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A horizontal line has a gradient of 0.
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m = 0
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The gradient of a vertical line is undefined.
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m is undefined
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Click Here for practice at calculating gradients.
Example
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Answer
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What is the gradient of the line below?
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What is the gradient of the line joining the points P (1, 2) to Q (4, 5)? |
Draw a diagram
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What is the gradient of the line joining the points M (2, -3) to N (-3, 5)? |
Draw a diagram
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