Friday

March 6, 2015

March 6, 2015

Posted by **Janet** on Saturday, April 16, 2011 at 5:09pm.

I worked through this but am not sure if I did it right or if I needed to work through as much as I did.

A=l*w

dA/dt=l*(dw/dt)+ w*(dl/dt = 45-16= 29cm^2/sec

P=2l*2w =

2(dl/dt)+2(dw/dt)=-4+6=2 cm/sec

Diagonal= (l^2+w^2)^1/2

dD/dt=(2l+2w)(.5)(l^2+w^2)^-.5

=(30+16)(.5)(225+64)^-.5

23/sqrt289=1.35 cm/sec

Did I need to do all this work, or just some of it or did I not even answer the orginally question?

- calculus -
**Damon**, Saturday, April 16, 2011 at 5:15pmDiagonal= (l^2+w^2)^1/2

then

dD/dt=(2 l dl/dt+2 w dw/dt)(.5)(l^2+w^2)^-.5

**Answer this Question**

**Related Questions**

calculus - The length l of a rectangle is decrasing at a rate of 5 cm/sec while ...

calculus-changing voltage - V = IR V is increasing at the rate of 1 volt/sec ...

calculus - Please check this for me: the lenght l, width w, & height h of a box ...

calculus - The Voltage v , Current I and Resistance R are related by the ...

calculus - The Voltage v , Current I and Resistance R are related by the ...

calculus - The voltage V (volts), current I (amperes), and resistence R (ohms) ...

Math - The length, l mm of an elastic string at time t seconds is given by l=t^3...

Calculus - Let V be the volume of a right circular cone having height h and ...

calculas - if the length is decreasing at a rate of 2 in./min. while width is ...

Calculus - The length of rectangle is increasing at a rate of 8cm/s and its ...