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-   -   Studying for a test and can't figure out some of the questions (https://www.askmehelpdesk.com/showthread.php?t=418818)

  • Nov 23, 2009, 10:00 PM
    DeweyFlash7
    Studying for a test and cant figure out some of the questions
    1.) 1/tanx+secx=cosx/sinx+1

    2.) secx-tanx=1-sinx/cosx

    3.) Usethe given informationtofind sin2x, cos2x, and tan 2x

    cscx=-5/2 270<x<360

    4.) Solve each equation for 0<x<360

    cosxtanx=1/2

    5.) Solve each equation for 0<x<2pie

    Root 3 cotx=2cosx
  • Nov 24, 2009, 05:53 AM
    Perito

    These appear to be identities.

    Memorize these important definitions:

    A.

    B.

    C.

    Also, remember this important identity:

    D.

    Here's the first problem as you wrote it.



    1. using items (A), you'd get:



    and



    This would only be true if , but that's not possible for all x. I believe you entere the problem incorrectly.

    For the others, do the same substitutions. Try to manipulate the equations so that what you see on the left is the same as the right. This is how you prove identities.
  • Nov 24, 2009, 08:11 AM
    Unknown008

    It might and could be 'solving' and not proving. The only problem is that it didn't mention the interval in 1 and 2 in contrast with the others.

    Also, is written as 'pi' and not 'pie' as in 'apple pie'.

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