A straight line anywhere that is not
vertical or horizontal which does not pass through the origin. It may be
solid or dotted. Clear "V" shapes score
M0.
M1
A straight line in the correct position.
Must have a positive gradient and lie
in quadrants 1,3 and 4. Ignore any
intercepts correct or incorrect. If there are other lines that are clearly
"construction" lines e.g. a line from 2i
to 3 they can be ignored. The line may be solid or dotted. However, if there are clearly several lines then score A0.
A1
(2)
Part (b)
The approaches below are the ones that have been seen most often. Apply the mark scheme to the overall method the candidate has chosen.
There may be several attempts:
- If none are crossed out, mark all attempts and score the best single complete attempt
- If some attempts are crossed out, mark the uncrossed out work
- If everything is crossed out, mark all the work and score the best single complete attempt
Note that the question does not specify the variables the candidates should work in so they may use: e.g. z=x+ iy and w=u+ iv or w=x+ iy and z=u+ iv or any other letters so please check the work carefully.
Note that the M marks are all dependent on each other.
