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anonymous
 one year ago
Related Rates Question Help!?!?!
The base of a triangle is decreasing at the rate of 1 ft/sec, while the height is increasing at the rate of 2 ft/sec. At what rate is the area of the triangle changing when the base is 10 ft and the height is 70 ft?
a)25
b)45
c)50
d)45
anonymous
 one year ago
Related Rates Question Help!?!?! The base of a triangle is decreasing at the rate of 1 ft/sec, while the height is increasing at the rate of 2 ft/sec. At what rate is the area of the triangle changing when the base is 10 ft and the height is 70 ft? a)25 b)45 c)50 d)45

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0only need help on this one and then i can do a whole bunch that are alike!!

phi
 one year ago
Best ResponseYou've already chosen the best response.1the area of the triangle is \[ A = \frac{1}{2} x y\] take the derivative with respect to t: \[ \frac{dA}{dt} = \frac{1}{2}\left( x \frac{dy}{dt}+ y \frac{dx}{dt}\right)\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0wouldn't the x and y disappear ?

phi
 one year ago
Best ResponseYou've already chosen the best response.1both x and y are variables and you must use the product rule

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0lovely okay got it thank you very much!

phi
 one year ago
Best ResponseYou've already chosen the best response.1d u v = u dv + v du if you have a constant, it can "go out front"

phi
 one year ago
Best ResponseYou've already chosen the best response.1unfortunately, I do not get any of your answer choices.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0wait would it be x dy/dt wouldn't it be x dx/dt

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay nvm product rule forgot

phi
 one year ago
Best ResponseYou've already chosen the best response.1the rule is d (uv) = u * dv + v * du or with x and y d/dt (xy)= x d/dt y + y * d/dt x

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0what are you getting?

phi
 one year ago
Best ResponseYou've already chosen the best response.1dx/dt= 1 dy/dt= 2 x=10 y=70 x dy/dt + y dx/dt = 10*2 + 70*1 = 2070= 50 then multiply by 1/2 to get 25 sq ft/ sec

anonymous
 one year ago
Best ResponseYou've already chosen the best response.025 is an answer choice though. wheres the problem?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh woops a should be a 25

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Thank you very much !!

phi
 one year ago
Best ResponseYou've already chosen the best response.1good luck on the other problems
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