Answer:
11 cm
Step-by-step explanation:
Given:
Length of new pencil = 19 cm
Length of pencil after using a month = 8 cm
Question asked:
The pencil is centimeters shorter now than when it was new = ?
Solution:
Length of new pencil = 19 cm
Length of pencil after using a month = 8 cm
The pencil is centimeters shorter now than when it was new = 19 cm - 8 cm
= 11 cm
Length of pencil has been used during a month = 11 cm
Answer:
0.8 kilowatt/hour
Step-by-step explanation:
divide 4/5, gives you .
The answer will be 2 cuz you multiply them at the answers
Answer:
x = 2 cm
y = 2 cm
A(max) = 4 cm²
Step-by-step explanation: See Annex
The right isosceles triangle has two 45° angles and the right angle.
tan 45° = 1 = x / 4 - y or x = 4 - y y = 4 - x
A(r) = x* y
Area of the rectangle as a function of x
A(x) = x * ( 4 - x ) A(x) = 4*x - x²
Tacking derivatives on both sides of the equation:
A´(x) = 4 - 2*x A´(x) = 0 4 - 2*x = 0
2*x = 4
x = 2 cm
And y = 4 - 2 = 2 cm
The rectangle of maximum area result to be a square of side 2 cm
A(max) = 2*2 = 4 cm²
To find out if A(x) has a maximum in the point x = 2
We get the second derivative
A´´(x) = -2 A´´(x) < 0 then A(x) has a maximum at x = 2