A wire 9 meters long is cut into two pieces. One piece is bent into a equilateral triangle for a frame for a stained glass ornament, while the other piece is bent into a circle for a TV antenna. To reduce storage space, where should the wire be cut to minimize the total area of both figures? Give the length of wire used for each: For the equilateral triangle:

Respuesta :

By second derivative test we see minima occurs at 3.39m .

Suppose that;

The length of  one wire = x m

And the length of other wire is = (9-x) m

Length of the wires and  bent into a equilateral  triangle for a frame for a stained glass ornament respectively.

Area of each side of equilateral triangle length = [tex]\frac{X}{3 }[/tex]  is [tex]\frac{\sqrt{3} }{4} ( \frac{x^{2} }{9} )[/tex] .

And that of circle given circumference ( 9−x )  is [tex]\frac{(9-x)^{2} }{4\pi }[/tex].

Total area =  f (x)  = [tex]\frac{\sqrt{3} }{4} (\frac{x^{2} }{9} ) + \frac{(9-x)^{2} }{4\pi }[/tex].

f'(x) =  [tex]\frac{\sqrt{3} x}{4} + \frac{x-9}{2\pi }[/tex]

To minimize we differentiate,  find the critical points and determine the local minima.

f′(x)=  0

we get ;

x =   [tex]\frac{36}{2\sqrt{3}x +4 }[/tex]

x = [tex]= \frac{36}{10.87\\+4}\\\\\frac{36}{14.87}[/tex]

By second derivative test we see minima occurs at 3.39m .

for the more details about minima click the link given below.

https://brainly.in/question/41264339