<span>2(30)+2x=860
This is because the 4 sides of the rectangle add up to the perimeter.
The unknown side is x, and there are two of those, and there are also two sides of 30.
They all add up to the perimeter.
So:
2(30) + 2x = 860</span>
The second derivative at the point (2,2) is 34/9
<u>Explanation:</u>
<u></u>
2x⁴ = 4y³
2x⁴ - 4y³ = 0
We first need to find dy/dx and then d²y/dx²
On differentiating the equation in terms of x
dy/dx = d(2x⁴ - 4y³) / dx
We get,
dy/dx = 2x³/3y²
On differentiating dy/dx we get,
d²y/dx² = 2x²/y² + 8x⁶/9y⁵

d²y/dx² = 34/9
Therefore, the second derivative at the point (2,2) is 34/9
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