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2013 Paper worked solutions (1 Viewer)

EdwardHeartsU

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I do not agree with your solutions for question 12 c and 15cii.
for question 12c:
the question states that kim's annual salary in the FIRST year is $30 000 and increases by 5% each SUBSEQUENT year and similarly for alex his annual salary in the FIRST year is $33000 and increase by $1500 each SUBSEQUENT year therefore KIM'S real salary in the 10th year is
30000(1.05)^9 since in the 1st year there is no income rise in the second year there is a rise in income of 1.05* that of the previous year and so on until the nth year where there will be an income of 30000(1.05)^(n-1). Therefore similarly for Alex his salary in the 10th year would be
33000(1500*9)
For question 15 cii)
the answer should be m<-2 and m>2 since this means there is one intercept on the left branch but no intercept on the right (- branch)but also m=2/3
the greater the abs(value for m) the steeper the curve. Also ur solution of m being between -2 and 2 only and not outside these limits is incorrect since if you sub in m=-6 then you only have 1 real solution therefore m<-2 also m is not between these two values since if you sub in m=0 then of course you will have two solutions.
Also for question 16a)
an alternative approach is equating 4x-3 with 5(the gradient of the line) to find the x intercept where the line is a tangent and then solving for c.
Lol Puneet, go tell that kid!
 

davidgoes4wce

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Q15 c (ii) is the tricky one for me, best way to do it is obviously to draw the graph and try to visualize where the intersections could occur with the function graph and ask yourself where the intersections could be. I think that tricked me was the inequality more than anything, I think to do this question well is try drawing the parallel values of |2x+1| and go from there.
 

davidgoes4wce

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The best way to do this question for Q 15 c (ii), is to draw a linear line from (0,1) through to the x-intercept of |2x-3|

Secondly, I reckon its best to then draw the line |2x+1| and try to visualise the slopes if m<-2 and m > 2. If m<-2, then the line does not intersect with the curve. However, if m<= 2 and m=>2 then the curve will intersect only once.

So the solutions is -2<m<= 2
 

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