Answer:
A rectangle is inscribed with its base on the x-axis and its upper corners on the parabola
y=5−x^2. What are the dimensions of such a rectangle with the greatest possible area?
Width =
Height =
Width =√10 and Height [tex]= \frac{10}{4}[/tex]
Step-by-step explanation:
Let the coordinates of the vertices of the rectangle which lie on the given parabola y = 5 - x² ........ (1)
are (h,k) and (-h,k).
Hence, the area of the rectangle will be (h + h) × k
Therefore, A = h²k ..... (2).
Now, from equation (1) we can write k = 5 - h² ....... (3)
So, from equation (2), we can write
[tex]A =h^{2} [5-h^{2} ]=5h^{2} -h^{4}[/tex]
For, A to be greatest ,
[tex]\frac{dA}{dh} =0 = 10h-4h^{3}[/tex]
⇒ [tex]h[10-4h^{2} ]=0[/tex]
⇒ [tex]h^{2} =\frac{10}{4} {Since, h≠ 0}[/tex]
⇒ [tex]h = ±\frac{\sqrt{10} }{2}[/tex]
Therefore, from equation (3), k = 5 - h²
⇒ [tex]k=5-\frac{10}{4} =\frac{10}{4}[/tex]
Hence,
Width = 2h =√10 and
Height = [tex]k =\frac{10}{4}.[/tex]
