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Mathematics · Oct / Nov 2025 · Paper 11 · Question 5

YMA01

As printed in the paper

The question as text

5. y C l P R M x O Figure 1 In this question you must show all stages of your working. Solutions relying on calculator technology are not acceptable.

Read automatically from the paper; the printed page above is exact.

Show the answer and mark scheme
  • 5(a)[3]

    2

    2

    2

    −

    +

    −

    +

    ±

    ±

    2

    x

    16

    x

    50

    2

    x

    8

    x

    25

    2(

    x

    ...)

    ...

    2

    2(

    x

    −

    4)

    +

    18

    Notes

    (a)

    2

    2

    2

    B1:

    Writes

    2

    x

    −

    16

    x

    +

    50

    in the form

    2(

    x ±

    ...)

    ±

    ...

    or e.g.

    ±

    ±

    2 (

    x

    ...)

    ...

    . Allow e.g. 16

    8

    2

    2

    M1: For

    x −

    ±

    or e.g.

    −

    ±

    −

    or

    −

    for −4

    2(

    4)

    ...

    2 (

    x

    4)

    ...

    4

    2

    2

    x −

    +

    A1:

    For

    2(

    4)

    18

    x −

    2

    +

    =

    Condone any spurious “ = 0” e.g.

    2(

    4)

    18

    0

  • 5(b)[5]

    18

    Eqn of l is

    y

    =

    ''

    ''

    x

    4

    or

    d

    y

    2

    y

    =

    2

    x

    −

    16

    x

    +

    50

    =

    4

    x

    −

    16

    d

    x

    18

    At M

    −

    =

    =

    =

    =

    4

    x

    16

    0

    x

    4,

    y

    18

    y

    x

    4

    9

    41

    2

    −

    +

    =

    2

    −

    +

    =

    or e.g.

    2

    +

    =

    2

    x

    16

    x

    50

    x

    4

    x

    41

    x

    100

    0

    2

    x

    50

    x

    2

    2

    2

    (

    )(

    )

    4

    x

    −

    41

    x

    +

    100

    =

    0

    x

    −

    4

    4

    x

    −

    25

    =

    0

    x

    =

    ...

    25

    x =

    o.e.

    4

    Notes

    (b)

    18

    c

    =

    = −

    M1:

    Deduces that equation of l is

    y

    ''

    ''

    x

    o.e. Follow through on

    y

    ''

    ''

    x

    from (a)

    4

    b

    Alternatively finds the coordinates of M (p, q) by using calculus and forms the equation

    2

    =

    −

    +

    = ±

    M1: Equates

    y

    2

    x

    16

    x

    50

    and their l of the form y

    mx

    and collects terms to form a 3 term

    =

    2

    −

    +

    quadratic equation. Condone a miscopy of

    y

    2

    x

    16

    x

    50

    as long as the intention is clear.

    A1:

    Correct 3 term quadratic equation. The terms do not have to all be on the same side but must be

    2

    collected so e.g.

    2

    x

    +

    50

    =

    41

    x

    is acceptable.

    2

    If the terms are all one side, the “= 0” may be implied by their attempt to solve.

    ddM1: Correct non calculator method of solving their 3TQ.

    Depends on both previous method marks.

    Do not allow for quoting the quadratic formula quoted followed by values e.g.

    2

    −±

    b

    b

    −

    4

    ac

    25

    2

    4

    x

    −

    41

    x

    +

    100

    =

    0

    x

    =

    =

    , 4

    2

    a

    4

    2

    41

    ±

    41

    −××

    4 4 100

    2

    But allow e.g.

    4

    x

    −

    41

    x

    +

    100

    =

    0

    x

    =

    2 4

    ×

    Do not allow obvious use of a calculator where the factors do not correspond with their 3TQ

    25

    25

    2

    (

    )

    e.g.

    4

    x

    −

    41

    x

    +

    100

    =

    0

    x

    −

    x

    −

    4

    =

    0

    x

    =

    , 4

    4

    4

    41

    25

    2

    (

    )(

    )

    or e.g.

    2

    x

    −

    x

    +

    50

    =

    0

    4

    x

    −

    25

    x

    −

    4

    =

    0

    x

    =

    , 4

    2

    4

    25

    2

    (

    )(

    )

    −

    +

    =

    −

    −

    =

    =

    or e.g.

    4

    x

    41

    x

    100

    0

    4

    x

    25

    4

    x

    16

    0

    x

    , 4

    4

    25

    25

    2

    (

    )

    but allow e.g.

    4

    x

    −

    41

    x

    +

    100

    =

    0

    4

    x

    −

    x

    −

    4

    =

    0

    x

    =

    , 4

    4

    4

    2

    −

    +

    =

    (

    −

    )(

    −

    )

    =

    (

    −

    )(

    −

    )

    =

    and allow e.g.

    4

    x

    41

    x

    100

    0

    4

    x

    25

    4

    x

    16

    4

    x

    25

    x

    4

    0

    x

    25

    25

    A1:

    x =

    only. If x = 4 is also seen, it must clearly be rejected or the

    x =

    clearly selected.

    4

    4

    Ignore any attempts to find y.

    9

  • 5(c)[2]

    ≤

    2

    −

    +

    ≥

    y

    2

    x

    16

    x

    50,

    y

    '' 2 x

    ''

    9

    2

    ≤

    ≤

    −

    +

    and 0

    ≤

    x

    ≤

    4

    Fully defined region E.g.

    2 x

    y

    2

    x

    16

    x

    50

    Notes

    Some candidates are answering (c) at the bottom of the first page of the question so please check there.

    Allow use of f (x) for y.

    2

    R

    ≤

    2

    x

    −

    16

    x

    +

    50

    Do not allow use of R for y e.g.

    or e.g. y > line

    B1ft: Uses C and l with inequalities in the correct directions and ignore any other inequalities for this

    mark.

    Allow strict or nonstrict inequalities and condone a mix of both for this mark.

    Follow through on their equation for l and their possibly incorrect completed square form for C.

    Examples:

    9

    9

    <

    2

    −

    +

    2

    y

    2

    x

    16

    x

    50

    and

    y

    ≥

    ''

    x

    ''

    or e.g.

    "

    2 x

    "

    <

    y

    <

    2

    x

    −

    16

    x

    +

    50

    2

    B1ft: Correct and fully consistently defined region and no incorrect inequalities.

    Follow through on their equation for l and their possibly incorrect completed square form for C.

    <

    <

    >

    For the restriction on x, allow e.g. 0

    x

    4

    or written separately as e.g.

    x

    0,

    x

    25

    <

    <

    a <

    0

    x

    a

    where

    4

    If extra inequalities are given that do not contradict then they can be ignored (see example below)

    Examples of full marks in (c):

    9

    2

    y

    ≤

    2

    x

    −

    16

    x

    +

    50,

    y

    ≥

    ''

    x

    ''

    ,

    x

    ≥

    0,

    x

    ≤

    4

    2

    9

    2

    <

    <

    −

    +

    <

    <

    "

    2 x

    "

    y

    2

    x

    16

    x

    50, 0

    x

    4

    9

    <

    <

    2

    −

    +

    <

    <

    >

    "

    2 x

    "

    y y

    ,

    2

    x

    16

    x

    50, 0

    x x

    ,

    6.25,

    y

    0

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