Respuesta :
Area of the big rectangle:
[tex]xy=27000 \\y= \frac{27000}{x} [/tex]
Total length of the fence:
[tex]\\P=2(x+y)+x \\P=2x+2y+x \\P=3x+2y [/tex]
Create function [tex]P(x)[/tex]:
[tex]\\P(x)=3x+2 \times \frac{27000}{x} \\P(x)= 3x+ \frac{54000}{x} [/tex]
Find the minimum value for [tex]x[/tex]:
[tex]\\P'(x)=3- \frac{54000}{x^2} \\P'(x)=0 \\3- \frac{54000}{x^2}=0 \\3x^2-54000=0 \\x^2=18000 \\x=\sqrt{18000} [/tex]
Find the minimum value for [tex]y[/tex]:
[tex]\\y= \frac{27000}{x} =\frac{27000}{\sqrt{18000}}[/tex]
Calculate the absolute minimum cost for which the fence for this project can be constructed:
[tex]\\C=2(x+y) \times \$5 + x \times \$2 \\C=2(\sqrt{18000}+\frac{27000}{\sqrt{18000}})\times \$5+\sqrt{18000} \times \$2 \\C \approx \$3622} [/tex]
[tex]xy=27000 \\y= \frac{27000}{x} [/tex]
Total length of the fence:
[tex]\\P=2(x+y)+x \\P=2x+2y+x \\P=3x+2y [/tex]
Create function [tex]P(x)[/tex]:
[tex]\\P(x)=3x+2 \times \frac{27000}{x} \\P(x)= 3x+ \frac{54000}{x} [/tex]
Find the minimum value for [tex]x[/tex]:
[tex]\\P'(x)=3- \frac{54000}{x^2} \\P'(x)=0 \\3- \frac{54000}{x^2}=0 \\3x^2-54000=0 \\x^2=18000 \\x=\sqrt{18000} [/tex]
Find the minimum value for [tex]y[/tex]:
[tex]\\y= \frac{27000}{x} =\frac{27000}{\sqrt{18000}}[/tex]
Calculate the absolute minimum cost for which the fence for this project can be constructed:
[tex]\\C=2(x+y) \times \$5 + x \times \$2 \\C=2(\sqrt{18000}+\frac{27000}{\sqrt{18000}})\times \$5+\sqrt{18000} \times \$2 \\C \approx \$3622} [/tex]
