Can someone help me with this pls?

Mathematics

1 answer:

madam [21]3 years ago

6 0

Please bare with me bc I’m bad at wording things, change it as you please!

It’s a minimum. I know that the function is a minimum because whenever there is a - in the beginning of the equation it flips your parabola over the x axis and my parabola becomes concave down. When my parabola is concave up I have a minimum, vise versa is a maximum. Because there isn’t a -, my parabola is concave up meaning the function has a minimum

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Could someone help out ? thanks

RUDIKE [14]

Since the area of the walkway is not given, it's substitution in the answer is x. You do have the measurements of the pool though. Area=length times width. 36 times 18 is 648. The area of the concrete is x-648 ft, because the pool is not apart of the concrete. The area of the walkway can be expressed by X-648 ft.

6 0

3 years ago

Can somebody explain this to me when 2du = 16xdx ???

tamaranim1 [39]

When you set $u=4x^2+4$ , you end up with the differentials $\mathrm du=8x\,\mathrm dx$ . Multiplying both sides by 2 gives $2\,\mathrm du=16x\,\mathrm dx$ .

Then the integral is

$\displaystyle\int_0^1\frac{16x}{(4x^2+4)^2}\,\mathrm dx=\int_4^8\frac2{u^2}\,\mathrm du=-\frac2u\bigg|_{u=4}^{u=8}=-2\left(\frac18-\frac14\right)=\frac14$