Answer:
10 ft x 10 ft
Area = 100 ft^2
Step-by-step explanation:
Let 'S' be the length of the southern boundary fence and 'W' the length of the eastern and western sides of the fence.
The total area is given by:

The cost function is given by:

Replacing that relationship into the Area function and finding its derivate, we can find the value of 'S' for which the area is maximized when the derivate equals zero:

If S=10 then W =20 -10 = 10
Therefore, the largest area enclosed by the fence is:

The answer is 112. 4/10 of 280. 280 divided by 10 equals 28. 28 x 4 = 112
Answer:
x = 
Step-by-step explanation:
Let the number be x.

x - 3 = 10x
9x = -3
x = 
Sin(13π/8) , is in quadrant IV so the angle will be negative, find the reference angle.
<span>sin(13π/8) = -sin(16π/8 - 13π/8) = -sin(3π/8) = -cos(4π/8 - 3π/8) = - cos(π/8). </span>
<span>Use half angle formula for cos(x): </span>
<span>cos²(x/2) = (cos(x) + 1) / 2 </span>
<span>Let x = π/4 </span>
<span>cos²(π/8) = (cos(π/4) + 1) / 2 </span>
<span>cos²(π/8) = (√(2) / 2 + 1) / 2 </span>
<span>cos(π/8) = √(√(2) / 4 + 1/2) </span>
<span>-cos(π/8) = -√((√(2) + 2) / 4)</span>
The y-intercept (or line intercept) is 1, and the slope is 3