Posted by **Anonymous** on Wednesday, November 21, 2012 at 9:21am.

QUESTION 3

A boat sails 30 miles to the east from a point P, then it changes direction and sails to the south. If this boat is sailing at a constant speed of 10 miles/hr, at what rate is its distance from the point P increasing

a) 2 hours after it leaves the point P

b) 7 hours after it leaves the point P

- calculus -
**Steve**, Wednesday, November 21, 2012 at 10:25am
at 10 mph, it is still going east at t=2

so, distance is increasing at 10 mph

at t=3, it turns south. After that, the distance d from P is

d^2 = 30^2 + (10(t-3))^2

2d dd/dt = 200(t-3)

at t=7, d=50

2*50 dd/dt = 200(4)

dd/dt = 8 mph

- calculus -
**kchik**, Thursday, November 22, 2012 at 6:06am
i'm still not understand for this conclution

- calculus -
**kchik**, Thursday, November 22, 2012 at 6:13am
*conclusion not conclution

- calculus -
**Stane**, Thursday, November 22, 2012 at 6:56am
where do you get 200(t-3)???

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