- #1

asdfsystema

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Here are 3 problems my teacher is giving us in preparation for the upcoming test... I'm pretty clueless ! hope you guys could clear up the confusion for me.

The pic:

1. So altitude is the height. What i get from this is that the height is increasing by 2 cm/min and the area is increasing by 4.5 cm/min. the question asks for what the rate of change is for the base when the height is 10.5cm and the area is 100cm. Do I start off by taking the differentiation?

2. Area of circle = pi*r^2

differentiate.

dA/dt = 2pi*r * dr/dt

dA/dt= 2pi(5) * 5

dA/dt= 50pi/sec

3. I am really confused about this one too. the equation is y= 3 sqrt(4x+4) and the poitn passes through (3,12). I tried graphing this and plotting the point and also graphing the line since its 3 units per second but i have no idea where to start this using calculus. my teacher does not allow us to use the calculator on tests.

Thank you.