Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: An angle is given to one significant figure as 7 degrees

  1. Sep 15, 2005 #1

    courtrigrad

    User Avatar

    An angle is given to one significant figure as 7 degrees, meaning thats its value is between 6.5 degrees and 7.5 degrees. Find the corresponding range of possible values of the cosine of the angle. Is this a case in which there are more significant figures in the result than in the input data?

    I know the answer to the last question is yes. When I type in [tex] cos(7) [/tex] I get 0.9925461516. Would I round this up to 1 degree, thus its range of values is between 0.5 degrees and 1.5 degrees?

    thanks
     
    Last edited by a moderator: Jan 3, 2014
    courtrigrad, Sep 15, 2005
  2. jcsd
    Phys.org - latest science and technology news stories on Phys.org
  3. Sep 16, 2005 #2

    whozum

    User Avatar

    The angle is between 6.5 and 7.5 degrees, but you aren't sure. It's asking you to find what range the cosine of that angle lies in.
     
    whozum, Sep 16, 2005
  4. Sep 16, 2005 #3

    HallsofIvy

    User Avatar
    Science Advisor

    The largest the angle can be is 7.5 degrees. What is the cosine of 7.5 degrees?

    The smallest the angle can be is 6.5 degrees. What is the cosine of 6.5 degrees?

    Now, what do YOU think the possible range for cosine is? You may notice that some of the digits in the two answers are the same. What would be a good way of reporting a single number to represent that range?
     
    HallsofIvy, Sep 16, 2005
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook