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## Homework Statement

A rocket has launched straight up, and its altitude is h = 10t2

feet after t seconds. You are on the ground 1000 feet from the launch site. The line

of sight from you to the rocket makes an angle θ with the horizontal. By how many

Radians per second is θ changing ten seconds after the launch?

It's a problem form MIT OpenCourseWare, and I know the solution is given, but I did it my way and (suprisingly) it doesn't work. What did I wrong?

The answer is 1/10

It's not a homework question, but I didn't want to spoil your Mathematics section :)

## Homework Equations

[tex]\frac{dh}{dt}=20t[/tex]

## The Attempt at a Solution

[tex]\theta=arctan\frac{h}{1000}[/tex]

[tex]\frac{d}{dt}(\theta=arctan\frac{h}{1000})[/tex]

[tex]\frac{d\theta}{dt}=\frac{1}{1+\frac{h^{2}}{1000^2}}\frac{dh}{dt}[/tex]

which is 100 ;/

Thanks for any help :)