Answer:
x = 10 cm, y = 5 cm gives a minimum area of 300 cm^2.
Step-by-step explanation:
V= x^2y = 500
Surface area A = x^2 + 4xy.
From the first equation y = 500/x^2
So substituting for y in the equation for the surface area:
A = x^2 + 4x * 500/x^2
A = x^2 + 2000/x
Finding the derivative:
dA/dx = 2x - 2000x^-2
dA/dx = 2x - 2000/x^2
This = 0 for a minimum/maximum value of A, so
2x - 2000/x^2 = 0
2x^3 - 2000 = 0
x^3 = 2000/ 2 = 1000
x = 10
Second derivative is 2 + 4000/x^3
when x = 10 this is positive so x = 10 gives a minimum value of A.
So y = 500/x^2
= 500/100
= 5.
Answer:
As below.
Step-by-step explanation:
The -4 shifts the graph to the right not the left.
The second error is the refection is over the x-axis not the y-axis.
22-7-7-7=1 this will show that you can subtract 7 three times from 22 and have a remainder of 1.
Answer:
x = 1
y = -3
Step-by-step explanation:
cos(pi) = -1
so many ways :
sqrt(0.5/2) = sqrt(0.5/2 × 8/8) = sqrt(4/16)
= sqrt(0.5/2 × 18/18) = sqrt(9/36)
= sqrt(1/4) = 1/2
"nicest" approach (all integers) :
3x² = sqrt(9)
3x² = 3
x² = 3/3 = 1
x = 1
2y = sqrt(36)
2y = 6
y = 6/2 = 3
one of them has to be negative (because cos(pi) = -1), so it has to be y, because 3x² cannot be negative with real numbers.
so, y = -3
-1 × 3×1²/(2×-3) = sqrt(0.5/2) = 1/2
-1 × 3/-6 = 1/2
3/6 = 1/2
1/2 = 1/2
correct
