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Simple Derivative Problem

  • Thread starter LyleCoff
  • Start date
  • #1
1
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Find the derivative of (4995)/(1+.12cosθ), when θ = 120°

My attempt:

d/dx [4995/(1+.12cosθ) = (4995)(-1)(1+.12cosθ)-2(.12)(-sinθ)

Letting θ = 120°...

= (4995)(-1)(1+.12(-1/2))-2(.12)(-[itex]\sqrt{3}[/itex]/2)


My calculator says that is about 587.478

But it's supposed to be about 10.253

I just started calculus, so I'm probably making some really basic mistake.
 

Answers and Replies

  • #2
Bacle2
Science Advisor
1,089
10
Results are usually done in radians instead of degrees. Have you tried doing your

computation in radians?
 
  • #3
LCKurtz
Science Advisor
Homework Helper
Insights Author
Gold Member
9,517
733
To add to what Bacle2 has said, your standard formulas for the derivatives are correct only when the angles are given in radians.
 

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