Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Math Help - Who knows Trigonometric Functions?

  1. #1
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1

    Who knows Trigonometric Functions?

    I have an assignment due today at 5 (around 3 hours) and I know I shouldn't of left it this late. I basically get nothing on it, and if anyone here could explain to me how to do it or go through the questions with me, it would be great.
    Thanks.

    Btw, it is grade 12 functions level.
    Last edited by mr fantastic; July 11th 2009 at 02:50 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    I have an assignment due today at 5 (around 3 hours) and I know I shouldn't of left it this late. I basically get nothing on it, and if anyone here could explain to me how to do it or go through the questions with me, it would be great. Thanks.

    Btw, it is grade 12 functions level.
    Please write the exact questions that you have.
    Last edited by mr fantastic; July 11th 2009 at 02:51 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Here is one of them:

    Prove:

    sec(x) = 2(cosxsin2x - sinxcos2x)/sin2x

    Prove:

    Follow Math Help Forum on Facebook and Google+

  4. #4
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Here is my full assignment:
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor alexmahone's Avatar
    Joined
    Oct 2008
    Posts
    1,074
    Thanks
    7
    Quote Originally Posted by Anonymous14 View Post
    Here is one of them:

    Prove:

    sec(x) = 2(cosxsin2x - sinxcos2x)/sin2x

    Prove:

    1) RHS=\frac{2(cosxsin2x - sinxcos2x)}{sin2x}

     = \frac{2sin (2x-x)}{sin 2x} {Using the sin (A-B) identity}

     =\frac{2sin x}{2sin x cos x} { sin 2x=2sinx cosx }

     =\frac{1}{cos x}

     =sec x= LHS

    ---------------------------------------------------------------------

    2) LHS=\frac{1-sin^2x}{cos x}

    = \frac{cos^2x}{cos x}

    = cos x ------------------------- (a)

    RHS=\frac{sin (2x)}{2sin (x)}

    =  \frac{2sin x cos x}{2 sin x}

    =cos x---------------------------(b)

    From (a) and (b),

    LHS=RHS
    Last edited by alexmahone; July 11th 2009 at 10:05 AM.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    Here is one of them:

    Prove:

    sec(x) = 2(cosxsin2x - sinxcos2x)/sin2x

    Prove:

    You know that

    \sin (A-B) = \sin A \cos B-\cos A\sin B

    \sin 2x = 2\sin x\cos x

    Right Side =\frac{2(\cos x \sin 2x - \sin x\cos 2x)}{\sin 2x}

    =\frac{\sin(2x-x)}{\sin 2x}

    =\frac{\sin x}{2\sin x \cos x}=\frac{1}{\cos x}

    =\sec x = Left side
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    Here is one of them:

    Prove:

    LS=\frac{1-\sin^2 x}{\cos x}=\frac{\cos^2 x}{\cos x}=\cos x

    RS= \frac{\sin 2x}{2\sin x}

    =\frac{2\sin x \cos x}{2\sin x} = \cos x

    LS=RS
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Thank you both so much. I will +rep you. I might have a few more questions that I don't understand.
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Follow Math Help Forum on Facebook and Google+

  10. #10
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    Here is my full assignment:
    Please see these two solution in attachment file, and more coming..........
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  11. #11
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Quote Originally Posted by Shyam View Post
    Please see these two solution in attachment file, and more coming..........
    Thanks so much. Please don't do number 6 because I already understand that question perfectly.
    Follow Math Help Forum on Facebook and Google+

  12. #12
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    See attachment,page2.
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  13. #13
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Thanks, Also, this one...

    sin(x) = ??????? similarly tan(pi - x) = ????????? verify on your calculator for x = 29, or angle of your choice.

    Is the first one cos(pi/2 - x) ?
    Last edited by mr fantastic; July 11th 2009 at 02:19 PM.
    Follow Math Help Forum on Facebook and Google+

  14. #14
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by Anonymous14 View Post
    Thanks so much. Please don't do number 6 because I already understand that question perfectly.
    Any more questions?

    x = 29

    \sin 29^\circ = 0.48480962

    change  29^\circ into radians,

     29^\circ=29^\circ\times\frac{ \pi}{180}=0.506145483\; rad

    \tan(\pi-x)=\tan(\pi-0.506145483)=\tan(2.635447171)=-0.5543

    Did you get it???
    Last edited by mr fantastic; July 11th 2009 at 02:18 PM. Reason: Deleted Paypal details. Giving such information is totally inappropriate at MHF.
    Follow Math Help Forum on Facebook and Google+

  15. #15
    Banned
    Joined
    Jul 2009
    Posts
    8
    Awards
    1
    Quote Originally Posted by Shyam View Post
    Any more questions?

    x = 29

    \sin 29^\circ = 0.48480962

    change  29^\circ into radians,

     29^\circ=29^\circ\times\frac{ \pi}{180}=0.506145483\; rad

    \tan(\pi-x)=\tan(\pi-0.506145483)=\tan(2.635447171)=-0.5543

    Did you get it???
    Yup, Thanks again for all of your help.
    Last edited by mr fantastic; July 11th 2009 at 02:23 PM.
    Follow Math Help Forum on Facebook and Google+

Page 1 of 2 12 LastLast

Similar Math Help Forum Discussions

  1. Replies: 6
    Last Post: August 29th 2010, 05:23 PM
  2. Replies: 3
    Last Post: February 23rd 2010, 04:54 PM
  3. Replies: 2
    Last Post: February 19th 2010, 10:37 AM
  4. Trigonometric functions, arcus functions
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: October 2nd 2009, 04:48 AM
  5. trigonometric functions
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: July 26th 2009, 10:36 PM

Search Tags


/mathhelpforum @mathhelpforum