coordinate geometry

Question 1

how do you sketch a straight line graph?

Answer 1

find x intercept and y intercept usually

Question 2

how do you find the distance between points on a line?

Answer 2

apply pythagoras to the differences of their x and y coords.

Question 3

when given area or intersection problems on coordinate geometry, how are these solved?

Answer 3

DRAW A DIAGRAM. tis will help to create triangles, etc. and will allow normal geometric problem solving to be used.

Question 4

how do you show inequalities on a graph?

Answer 4

draw the line/curve using convention of dashed line for greater/less than and solid line for greater than or equal to/less than or equal to.

identify which side of a line/curve will agree with the inequality (test a coord to see if it is </> the line required)

shade in the required region and mark with R

for multiple inequalities, draw all lines first and then test regions to see which agrees with all.

Question 5

what is the formula to find the gradient of a straight line between two points?

Answer 5

m = (Y2 - Y1) / (X2 - X1*)

Question 6

what is the pythagorean formula used to find the length of a line joining 2 points?

Answer 6

AB = √(X2 - X1) + (Y2 - Y1)

Question 7

formula to find the midpoint of a line joining 2 points?

Answer 7

M =
([X1 + X2] / 2 , [Y1 + Y2] / 2 )

Question 8

what is the formula for the equation of a line passing though a point with gradient m?

Answer 8

Y - Y1 = m (X - X1)

Question 9

how do the gradients of parallel lines compare?

Answer 9

they are the same, m1 = m2

Question 10

how do the gradients of 2 perpendicular lines compare?

Answer 10

m1 = -1 / m2
they are negative reciprocals