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Date May 2011 Marks available 2 Reference code 11M.1.sl.TZ2.5
Level SL only Paper 1 Time zone TZ2
Command term Find Question number 5 Adapted from N/A

Question

The straight line L passes through the points A(1, 4) and B(58) .

Calculate the gradient of L .

[2]
a.

Find the equation of L .

[2]
b.

The line L also passes through the point P(8y) . Find the value of y .

[2]
c.

Markscheme

845(1)     (M1)

Note: Award (M1) for correct substitution into the gradient formula.

 

23 (460.667)     (A1)     (C2)

[2 marks]

a.

y=23x+c     (A1)(ft)

Note: Award (A1)(ft) for their gradient substituted in their equation.


y=23x+143     (A1)(ft)     (C2)

Notes: Award (A1)(ft) for their correct equation. Accept any equivalent form. Accept decimal equivalents for coefficients to 3 sf.

 

OR

yy1=23(xx1)     (A1)(ft)

Note: Award (A1)(ft) for their gradient substituted in the equation.

 

y4=23(x+1)     OR     y8=23(x5)     (A1)(ft)     (C2)

Note: Award (A1)(ft) for correct equation.

[2 marks]

b.

y=23×8+143     OR     y4=23(8+1)     OR     y8=23(85)     (M1)

Note: Award (M1) for substitution of x=8 into their equation.

 

y=10 (10.0)     (A1)(ft)     (C2)

Note: Follow through from their answer to part (b).

[2 marks]

c.

Examiners report

Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method. On a number of scripts, part (a) produced a rather curious wrong answer of 8.2 following a correct gradient expression. It would seem that this was as a result of typing into the calculator 84÷5+1.

a.

Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method.

b.

Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method.

c.

Syllabus sections

Topic 5 - Geometry and trigonometry » 5.1 » Equation of a line in two dimensions: the forms y=mx+c and ax+by+d=0 .
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