co,ordinate geometry

co,ordinate geometry

1. y=3x-4. 3 is the gradient as number before x. 4 is the y intercept as single number.

   • you may have to rearrange equations eg: 2y=3x+1 would rearange to be y=3/2 +1/2

2. To find the gradient of a line you use the two set of coordinates given and place them into the fomulae m= y^2-y^1 ____________ x^2-x^1

   • y^2 is the highest set of coordinates and y^1 the lower

3. If you have a gradient and a point on the line you can find the equation of the line using this formula: y-y^1 = m(x-x^1)

   • An example of this is; find the equation of the line with the gradient s that passes throigh the point (3,2). The working for this anser would be as follows: 1)) y-2=5(x-3) 2)) y-2=5x-15 3)) y=5x-13

4. when receiving a question such as: the line y=4x-8 meets the x axis at the the point p. work out the co, ordinates of p. The first thing to think if is that we already know what the y coordinate will be so we have to work out the x. to work out the x we put the y as 0 so in this case 0=4x-8 we then rearrange to get x on its own 8=4x, x=2. this then gives us our answer.

   • when ever we are trying to find out the coordinates in which we already have the equation for we place x or y at 0. If we are trying to find the x we put y as 0 and if we are trying to find the x we place x as 0.

5. The gradient can be both posittive and negative, however this will change the direction of the lines. if the gradient is positive the line will end in the top right box however if it is negative it will end in the bottom right.

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