Results 1 to 2 of 2

Math Help - Compound Angle problems

  1. #1
    Junior Member madmax29's Avatar
    Joined
    Feb 2009
    Posts
    33

    Exclamation Compound Angle problems

    Compound Angle problems

    I have the equation 5.5 Cos t + 7.8 Sin t
    i) i have to express it in the form R Sin (t + ᾀ) <---- ᾀ alpha)
    ii) solve for 0 < Θ < 2Π for 5.5 Cos t + 7.8 Sin t = 4.5

    for part i) got 5.5 Cos t + 7.8 Sin t = R Sin (t + ᾀ)
    where = R[sin t Cos ᾀ + Cos t Sin ᾀ]
    = (R Cos ᾀ) Sin t + (R Sin ᾀ) Cos t
    the next stage i have to get it into R = SQUAREROOT(a^2 + b^2)
    unsure how to do this???


    also my current attemp at part ii has led me with incorrect answers?? any help?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by madmax29 View Post
    Compound Angle problems

    I have the equation 5.5 Cos t + 7.8 Sin t
    i) i have to express it in the form R Sin (t + ᾀ) <---- ᾀ alpha)
    ii) solve for 0 < Θ < 2Π for 5.5 Cos t + 7.8 Sin t = 4.5

    for part i) got 5.5 Cos t + 7.8 Sin t = R Sin (t + ᾀ)
    where = R[sin t Cos ᾀ + Cos t Sin ᾀ]
    = (R Cos ᾀ) Sin t + (R Sin ᾀ) Cos t
    the next stage i have to get it into R = SQUAREROOT(a^2 + b^2)
    unsure how to do this???


    also my current attemp at part ii has led me with incorrect answers?? any help?
    see post #3 here

    does that help?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. compound angle formula problems
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: December 9th 2009, 06:44 AM
  2. Compound Angle
    Posted in the Calculus Forum
    Replies: 4
    Last Post: November 9th 2009, 08:43 PM
  3. Replies: 8
    Last Post: May 13th 2009, 03:25 PM
  4. Compound Angle Identities
    Posted in the Trigonometry Forum
    Replies: 4
    Last Post: December 11th 2008, 02:11 PM
  5. Compound angle formulae
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: January 13th 2008, 04:02 PM

Search Tags


/mathhelpforum @mathhelpforum