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secondary 4 | E Maths

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Chloe

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Plz solve with steps thanks

Date Posted: 10 months ago
Views: 259

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1st
hope this helps.
Date Posted: 10 months ago
Chloe
10 months ago
How did px suddenly became this (12-2.4x)
Snell
10 months ago
it is not P(x),
it is P'(x), a derivative of P(x).
meaning
differentiate P(x) wrt x
Chloe
10 months ago
Ok thanks for your help! Though we do not learn differentiation in sec 4
Snell
10 months ago
oh, u dun take AMath?

then to find the max. u hv to follow a tedious method of completing the square to find the max point.

complete the square:
P(x) = -1.2x² + 12x - 5
= -1.2(x²-10x) - 5
= -1.2(x²-10x+25) - 5 +30
= -1.2(x-5)² + 25

this means max pt is at (5, 25).

how?
bcos of (x-5)², we know the x-coordinates of max pt is 5.
[equate x-5=0 => x=5]

then subst. x=5 into P(x):
P(x) = -1.2(5-5)² + 25
= 0 + 25 = 25

max profit P(x) = 25.

and

u r welcome!
Chloe
10 months ago
This is what im looking for thank you so much
Chloe
10 months ago
So the ans would be 25000?
Snell
10 months ago
nope. sorry.

the qn asks for quantity of products, i.e. x ;
we found x = 5 ;

so the ans is 5000, bcos the qn states x is in thousands.

leaving this thread now.
any more qns, send to: [email protected]
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