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D1

It's actually a question about the objective function.

'The objective is to maximise 3x+y. Find the optimal values of x and y. You must make your method clear.'

I've drawn the objective line in and used the ruler method to determine the optimal vertex. Can I judge by eye the coordinates of the vertex? I get (7.08, 3.56) when the mark scheme says (7.06,3.53)

How accurate do they want the answer?
(May 2011)
Reply 1
Avatar for Smaug123
Smaug123
15
I would have thought you should use a non-graphical method, but bear in mind that I'm not a teacher or examiner. If the answer was listed in the mark scheme to three SF, then they wanted it calculated rather than guessed from a graph.
Reply 2
Avatar for TenOfThem
TenOfThem
18
Original post by bubbles95
It's actually a question about the objective function.

'The objective is to maximise 3x+y. Find the optimal values of x and y. You must make your method clear.'

I've drawn the objective line in and used the ruler method to determine the optimal vertex. Can I judge by eye the coordinates of the vertex? I get (7.08, 3.56) when the mark scheme says (7.06,3.53)

How accurate do they want the answer?
(May 2011)


They want you to solve the simultaneous equations and get the right answer
Reply 3
Avatar for bubbles95
bubbles95
OP
In the mark scheme it says on the notes,

(b)1M1 Drawing objective line or its reciprocal OR testing two vertices in the feasible region (see list above) points correct to 1 dp.
1A1 Correct objective line OR two points correctly tested (1 dp ok)
2DM1 Calculating optimal point either answer to 2 dp or better or using S.E’s (correct 2 equations for their point + attempt to eliminate one variable.); OR Testing three points correctly and optimal one to 2dp.
2A1 CAO 2 dp or better

:/
Reply 4
Avatar for TenOfThem
TenOfThem
18
Original post by bubbles95
In the mark scheme it says on the notes,

(b)1M1 Drawing objective line or its reciprocal OR testing two vertices in the feasible region (see list above) points correct to 1 dp.
1A1 Correct objective line OR two points correctly tested (1 dp ok)
2DM1 Calculating optimal point either answer to 2 dp or better or using S.E’s (correct 2 equations for their point + attempt to eliminate one variable.); OR Testing three points correctly and optimal one to 2dp.
2A1 CAO 2 dp or better

:/


As I said ... simultaneous equations
Reply 5
Avatar for bubbles95
bubbles95
OP
Okay thanks
ready for the exam bro?

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