A transformation that maps P to Q is a reflection in the line \(\quad x = -1\)
Make one criticism of the statement. [1 mark]
(b) Here are two shapes, C and D.
Here is a statement.
A transformation that maps C to D is a rotation through \(90^\circ\) anticlockwise.
Make one criticism of the statement. [1 mark]
Mark scheme (a)
Answer
Mark
Comments
Says that the wrong line has been given or says that for the given reflection the image would be in the second quadrant (may be implied by sketch) or says that the given line is vertical or gives the coordinates of at least one image point under the given reflection or says that after the given reflection, a rotation \(180^\circ\) (centre \((-1, -1)\)) or an enlargement, scale factor \(-1\) (centre \((-1, -1)\)) is needed
B1
eg the line should be \(y = -1\)
eg the triangle would move to the other side of the \(y\)-axis
eg \(x = -1\) is vertical
eg (1, 1) would move to \((-3, 1)\) (1, 3) would move to \((-3, 3)\) (4, 1) would move to \((-6, 1)\)
Additional guidance
It is the wrong line/axis (of reflection)
B1
It’s not \(x = -1\)
B1
The line should be horizontal
B1
\(y = -1\)
B1
\(x = -1\) line drawn with explanation that it is incorrect
B1
Q should be to the left of P
B1
Correct line drawn, with indication that it should be that line
B1
Correct statement with irrelevant statement eg It’s the wrong line and Q is in the wrong place
B1
Correct line drawn, but no explanation or equation given
B0
\(x = -1\) line drawn with no explanation that it is incorrect
B0
It should be reflected in the \(y\)-axis
B0
It is not a reflection in \(x = -1\)
B0
Should be rotation about \(y = -1\)
B0
They are not an equal distance from each other
B0
It should be the point \(x = -1\)
B0
Q is in the wrong place
B0
It is a reflection in the \(x\)-axis then a translation by \(\begin{pmatrix} 0 \\ -2 \end{pmatrix}\)
B0
Correct statement with incorrect statement eg It’s the wrong line, it should be \(x = -2\)
B0
If more than one image point is given, they must all be correct
Mark scheme (b)
Answer
Mark
Comments
Should say the centre of rotation (is \(O\))
B1
oe statement accept ‘axis of rotation’ or ‘point’
Additional guidance
Allow origin or (0, 0) for \(O\)
Should be about \(O\)
B1
There is no centre
B1
It should be around a point
B1
It doesn’t give the coordinates
B1
Should/could be \(270^\circ\) clockwise about \(O\)
B1
Should/could be \(270^\circ\) clockwise
B0
Should be rotation through \(90^\circ\) clockwise about \(O\)
B0
It is a reflection \(90^\circ\) anticlockwise with centre \(O\)
B0
It’s not reflected on a point
B0
Doesn’t say which line you’re turning around
B0
Correct statement with incorrect statement eg It should give a centre of rotation at (0, 1)
