## Army Helicopter math problem

Math help on Calculating limits of functions, Differentiation of a product, Differentiation of a quotient, Composition of functions, Chain Rule, Variations, Extremums: Maximums, Minimums, Increasing Functions, Decreasing Functions, Constant Functions, Differential Equations, Growth of a Population, Formulas, Integration by Parts, Change of Variables; Double Integrals, Triple Integrals, Multiple Integrals, Integrals with a Parameter, Area, Volume, Approximations on My Math Forum.

### Army Helicopter math problem

A Black Hawk Down Army million dollar helicopter is flying a mile high in the sky. It flyes over computerized cannons that are at Desert Ground Level. When the Army helicopter is 10 miles out horizontally from these cannons the cannons computers sense the helicopters distance is changing at a rate of 200mph.

How fast is the Black Hawk Down Helicopter traveling.

Who can solve
“If you can't explain it simply, you don't understand it well enough”

A.I.
mathkid

Posts: 866
Joined: Fri Aug 03, 2012 2:47 pm
Location: South Carolina

### Re: Army Helicopter math problem

I can. Thank you for your concern.

Or did you want someone to solve it for you? I won't but I will give some pointers- you can use the Pythagorean theorem to write the direct distance from the cannon to the helicopter (that's the hypotenuse of a right triangle) in terms of the horizontal distance (one of the legs- the other leg is the constant altitude). Then differentiate both sides of that equation with respect to time.
HallsofIvy
Super User

Posts: 2341
Joined: Tue Sep 11, 2007 9:14 am

### Re: Army Helicopter math problem

HallsofIvy wrote:I can. Thank you for your concern.

Looks like SOMEONE is vying for "funniest member, 2012"!!

p.s. due to my low activity level of late, I might need someone else to run the awards this year

The Chaz
Global Moderator

Posts: 2766
Joined: Mon Nov 23, 2009 9:34 pm
Location: Northwest Arkansas

### Re: Army Helicopter math problem

haha you know what they say,

MISERY LOVES COMPANY LOL well I shall not participate!
“If you can't explain it simply, you don't understand it well enough”

A.I.
mathkid

Posts: 866
Joined: Fri Aug 03, 2012 2:47 pm
Location: South Carolina

### Re: Army Helicopter math problem

I would draw a sketch such as:

coptercannon.jpg (9.27 KiB) Viewed 105 times

We are given:

$\frac{d}{dt}$$\sqrt{x^2(t)+1}$$=200\text{ mph}$

Perform the indicated differentiation, and solve for $\frac{d}{dt}$$x(t)$$$.
Living in the pools, They soon forget about the sea...— Rush, "Natural Science" (1980)

MarkFL
Global Moderator

Posts: 11318
Joined: Thu Jul 01, 2010 3:14 am
Location: St. Augustine, FL., U.S.A.'s oldest city

### Re: Army Helicopter math problem

practice practice practice I need more practice
“If you can't explain it simply, you don't understand it well enough”

A.I.
mathkid

Posts: 866
Joined: Fri Aug 03, 2012 2:47 pm
Location: South Carolina

### Re: Army Helicopter math problem

By the way, while the U.S. army does use a "Black Hawk" helicopter, calling it a "Black Hawk down" helicopter is really, really, tacky!
HallsofIvy
Super User

Posts: 2341
Joined: Tue Sep 11, 2007 9:14 am

### Re: Army Helicopter math problem

@HallsofIvy I agree with you
“If you can't explain it simply, you don't understand it well enough”

A.I.
mathkid