Saturday

December 20, 2014

December 20, 2014

Posted by **Daniel** on Sunday, March 4, 2012 at 9:06pm.

I drew a diagram and figured out I need to find dd/dt which is the distance of the plane from the radar station over time

I found y to be the altitude of the plane (1 mi)

I also found x to be the distance away from the radar station (2 mi)

dc/dt = 500 mi/h

I noticed I could use the pythagorean equation here.

d^2 = x^2 + y^2

I solved for d to be sqrt(5)

and I differentiated the equation to be 2d*(dd/dt) = 2x*(dx/dt) + 2y*(dy/dt)

y is constant therefore dy/dt = 0

I evaluated it to be (dd/dt) = [2(2)(500)]/(2sqrt(5)) or 1000/sqrt(5)

which is equivalent to 447mi/hr

My problem is the answer is 250sqrt(3) which is 433mi/hr

What am I doing wrong?

- calculus -
**Steve**, Monday, March 5, 2012 at 4:28amapparently 2 miles is the straight-line distance, so d=2 and x=sqrt(3)

2d dd/dt = 2x dx/dt

2(2) dd/dt = 2sqrt(3)*500

dd/dt = 250sqrt(3)

- calculus -
**Daniel**, Monday, March 5, 2012 at 9:44amI'm confused as to how you got d =2 and x=sqrt(3)

**Answer this Question**

**Related Questions**

CALCULUS - A plane, flying horizontally at an altitude of 1 km and a speed of ...

calculus - a plane flying horizontally at an altitude of 2 mi and a speed of 460...

calculus - A plane flying horizontally at an altitude of 1 mi and a speed of 560...

Cal - A plane flying horizontally at an altitude of 3 mi and a speed of 480 mi/h...

Calc - A plane flying horizontally at an altitude of 1 mi and a speed of 510 mi/...

math cal - A plane flying horizontally at an altitude of 3 mi and a speed of 480...

Calc - How do I do this related rates problem? A plane flying horizontally at an...

calculus - A plane that is flying horizontally at an altitude of 6 kilometers ...

Calc - A plane that is flying horizontally at an altitude of 6 kilometers and a ...

Calculus - A plane flying with a constant speed of 4 km/min passes over a ground...