Answer:
a) ⅓ units²
b) 4/15 pi units³
c) 2/3 pi units³
Step-by-step explanation:
4y = x²
2y = x
4y = (2y)²
4y = 4y²
4y² - 4y = 0
y(y-1) = 0
y = 0, 1
x = 0, 2
Area
Integrate: x²/4 - x/2
From 0 to 2
(x³/12 - x²/4)
(8/12 - 4/4) - 0
= -⅓
Area = ⅓
Volume:
Squares and then integrate
Integrate: [x²/4]² - [x/2]²
Integrate: x⁴/16 - x²/4
x⁵/80 - x³/12
Limits 0 to 2
(2⁵/80 - 2³/12) - 0
-4/15
Volume = 4/15 pi
About the x-axis
x² = 4y
x² = 4y²
Integrate the difference
Integrate: 4y² - 4y
4y³/3 - 2y²
Limits 0 to 1
(4/3 - 2) - 0
-2/3
Volume = ⅔ pi
The answer is 15w^2 + 225w
Key:
^ - Means that it is an exponent, in case you didn't know :)
Answers:
- The direct variation equation is y = 5x
- If x = 4, then y = 20
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Explanation:
Let's say that the letter k replaces the green box
We have the equation y = kx
Plug in (x,y) = (7,35) to get the equation 35 = k*7
Dividing both sides by 7 leads to k = 5
Therefore, the direct variation equation is y = 5x
We can check this by plugging in x = 7
y = 5x
y = 5*7
y = 35
So x = 7 leads to y = 35 as expected.
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Do the same for x = 4
y = 5x
y = 5*4
y = 20 when x = 4
Side note: direct variation equations always go through the origin.
Photomath is the best for fractions, decimals ect. You could also try a scientific calculator.
