Wednesday

March 4, 2015

March 4, 2015

Posted by **Allison** on Tuesday, July 26, 2011 at 6:21pm.

- Calculus -
**Reiny**, Tuesday, July 26, 2011 at 8:28pmLet the time passed since the northbound ship left the dock be t hrs

Make a sketch

Distance traveled by northbound boat is 20t

distance from dock of westbound boat is 15-15t.

let the distance between them be D

D^2 = (20t)^2 + (15-15t)^2

= 400t^2 + 225 - 450t + 225t^2

= 625t^2 - 450t + 225

2D dD/dt = 1250t - 450

dD/dt = (625t - 225)/d

= 0 for a max/min of D

625t = 225

t = 225/625 = .36

so the time is .36 hours past 2:00 pm

.36 hrs = 21.6 minutes or 21 minutes 36 seconds

time is 2:21:36 PM

- Calculus -
**Allison**, Wednesday, July 27, 2011 at 11:32amTHANK YOU! I get it now!

**Answer this Question**

**Related Questions**

math - a boat leaves a dock at 2:00pm ,heading west at 15 km/h. another boat ...

Calculus - a boat leaves a doct at 2:00pm, heading west at 15km/h. Another boat ...

calculus - a boat leaves a dock at 2:00 pm and travels due south at a speed of ...

calculus - Boat A leaves the dock at 12pm heading due South at a constant speed ...

Calculus (math) - A boat leaves a dock at 2:00 P.M. and travels due south at a ...

Calculus (math) - A boat leaves a dock at 2:00 P.M. and travels due south at a ...

Calculus - Suppose that two boats leave a dock at different times. One heads due...

calculus - A boat is pulled into a dock by a rope attached to the bow of the ...

Calculus Practice Problems - A boat is pulled into a dock by a rope attached to...

calculus - A boat is pulled into a dock by a rope attached to the bow of the ...