Question

revision on integration and differentiation

Answer 1

hey!

Answer 2

shall we start

Answer 3

certainly

Answer 4

follow this http://www.bbc.co.uk/scotland/learning/bitesize/higher/maths/calculus/

Answer 5

1.Find the maximum value of the product of 2 nos if their sum is 12

Answer 6

So, we're maximizing "xy" if "x + y = 12"...

I think if we rewrite the second equation with an independent variable, then we can clean up the first expression as a one-variable expression, and then find the horizontal tangent of that
x + y = 12
y = 12 - x

xy <- y=12-x
x(12 - x)

Answer 7

hmm then?

Answer 8

you can multiply it out and then take the derivative
once you have the derivative, you set that equal to 0 to find the point of a horizontal tangent, since that will be the maximum (not really rigorous in showing that, but its an upside-down parabola so it has one horizontal tangent at the maximum point)

Answer 9

x(12 - x) = 12x - x^2
d/dx( 12x - x^2 ) = 12 - 2x
12 - 2x = 0
-2x = -12
x = 6

then we have to go back to that equation to find y's value

y = 12 - x
y = 12 - 6
y = 6

xy = 6(6)
= 36

Answer 10

wow thanks next one

Answer 11

2 A printed page is required to contain k square units of printed matter .Side margins of width a and top bottom margins of width b are required .Find the length of the printed lines when the page is designed top use the least paper

Answer 12

is that all the information?

Answer 13

ys

Answer 14

interesting... i'll have to think about that one a bit

Answer 15

k post it here when u get an idea iw ill wait

Answer 16

Well, since there's no numerical information given, i think the final answer isn't going to be a number, probably an expression with the k.
That's the picture... hmm