Answer:
x = 
Step-by-step explanation:
Given function;
y = 5 + x - x²
To find the maximum value, follow these steps
(i) Find the first derivative (which is the slope) of the given function with respect to x. i.e;
= 
= 
= 
(ii) From the result in (i) determine the value of x for which the slope is zero. i.e.
x for which
1 - 2x = 0
=> 1 = 2x
=> x =
Therefore, the value of x for which the function is maximum is
Answer:
1. x = 15 in
2. x = 8 m
Step-by-step explanation:
1. Given:
length = 10 in
width = 3 in
height = x in
surface area of the rectangular prism = its volume
Required:
Value of x
Area = 2(wl + hl + hw)
Volume = l*w*h
Therefore:
2(3*10 + x*10 + x*3) = 10*3*x
2(30 + 10x + 3x) = 30x
2(30 + 13x) = 30x
60 + 26x = 30x
Subtract 26x from both sides
60 + 26x - 26x = 30x - 26x
60 = 4x
Divide both sides by 4
60/4 = 4x/4
15 = x
x = 15 in
2. Given:
length = 8 m
width = 4 m
height = x m
surface area of the rectangular prism = its volume
Required:
Value of x
Area = 2(wl + hl + hw)
Volume = l*w*h
Therefore:
2(4*8 + x*8 + x*4) = 8*4*x
2(32 + 8x + 4x) = 32x
2(32 + 12x) = 32x
64 + 24x = 32x
Subtract 24x from both sides
64 + 24x - 24x = 32x - 24x
64 = 8x
Divide both sides by 8
64/8 = 8x/8
8 = x
x = 8 m
