A particle moves along the curve y = 5x2 – 1 in such a way that the y value is decreasing at the rate of 2 units per second. At what rate is x changing when x = 1?

Question

anonymous · Answer

@@welshfella

anonymous · Answer

@welshfella

anonymous · Answer

@ganeshie8 @Destinymasha @e.mccormick @EclipsedStar @Directrix plz help :)

ribhu · Answer

at what rate y is changing i guess ur question needs correction @mathrulezz

anonymous · Answer

haha sorry i think they posted it on my website wrong :) but yes i guess that's what they mean :)

jhannybean · Answer

rate of change = slope of the given  function = derivative.

anonymous · Answer

okay so i have 2 find the derivatiev ? :)

jhannybean · Answer

at each time interval, you're going to have a different rate of change.

anonymous · Answer

10x is the derivative :D

jhannybean · Answer

Yep, you're finding the derivative.

anonymous · Answer

but it asks at what rate is x changing when x = 1

jhannybean · Answer

y' = 10x , what is x when y' = 2 units/sec?

anonymous · Answer

1/5 :) thanku!

anonymous · Answer

so its decreasing?

jhannybean · Answer

That's what your problem says :)

anonymous · Answer

graCIAS! thank u so much

jhannybean · Answer

No problem

ribhu · Answer

y = 5x^2 
dy/dt = 10xdx/dt;
rate of change of y is given and you have to calculate rate of change of x at x=1. 
dy/dt = -2 since it is decreasing. 
so dx/dt = -1/5. change of rate of x

ribhu · Answer

@Jhannybean i am also correct with this one.

jhannybean · Answer

There you go, you are right.

jhannybean · Answer

Because y and x are both changing across a curve with respect to time.