A jet flying due north at 8km/min passes 2km directly above a plane flying due wast at 4km/min. How quickly are they separating when the jet is 16km away from the crossover.

Question

anonymous · Answer

Did I draw this correctly?
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misty1212 · Answer

HI!!

misty1212 · Answer

looks good to me

misty1212 · Answer

then pythagoras finishes it

misty1212 · Answer

well pythagoras and a bunch of other calculations ...

anonymous · Answer

I'm not getting the correct answer :(

freckles · Answer

can i see your equations you used?
And what you got after differentiating?
And your final solution.

anonymous · Answer

I'm not sure if I did it right, but here it goes...
I first find x and the answer was 6sqrt7 m by using x^2+y^2=D^2
then I use this equation:
2x(dx/dt)+ 2y(dy/dt)=2D(dD/dt) and sub in all the values in
2(6sqrt7)(8)+0=2(16)(dD/dt)
and final answer is 96sqrt7/32, which is not the correct answer. (Correct answer is 80/9km/min)

freckles · Answer

why is 2y(dy/dt)=0?

freckles · Answer

in your picture you said dy/dt=4

anonymous · Answer

oops!

anonymous · Answer

I was thinking of a different scenerio on another question

freckles · Answer

$$2(6 \sqrt{7})8+2(2)(4)=2(16) \frac{dD}{dt}$$

freckles · Answer

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