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    Simplify:

    cos4x + 2sin2xcos2x + sin4x
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    try factorise, btw i think u may have made a typo on the second term the cos^4x bit
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    (Original post by cj_134)
    try factorise, btw i think u may have made a typo on the second term the cos^4x bit
    thx..yh i changed it nw..
    i tried factorising but i dnt get it!!
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    (Original post by tfdes)
    thx..yh i changed it nw..
    i tried factorising but i dnt get it!!
    Think about what (x+y)^2 comes out as and try to relate it to this question.
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    (Original post by tfdes)
    thx..yh i changed it nw..
    i tried factorising but i dnt get it!!
    try let x = cos^2 theta and y = sin^2 theta , you get
    x^2 +2xy + y^2
    factors as
    (x+y)^2
    put x and y back in
    (cos^2 theta + sin^2 theta)^2
    im sure u can take it from here
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    (Original post by cj_134)
    try let x = cos^2 theta and y = sin^2 theta , you get
    x^2 +2xy + y^2
    factors as
    (x+y)^2
    put x and y back in
    (cos^2 theta + sin^2 theta)^2
    im sure u can take it from here
    okk..i got it so far..but hw do i end it? final answer is 1..hw do i get tht?!?
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    it looks like a quadratic - factorise into (sin^2 x + cos^2 x) (sin^2 x + cos^2 x) (ie, it's squared)

    also sin^2 x + cos^2 x = 1 (pythagoras)

    so it's effectively 1 squared = 1 hope it helps!
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    (Original post by macccj)
    it looks like a quadratic - factorise into (sin^2 x + cos^2 x) (sin^2 x + cos^2 x) (ie, it's squared)

    also sin^2 x + cos^2 x = 1 (pythagoras)

    so it's effectively 1 squared = 1 hope it helps!
    pythagoras?? what?!? omg..im reali gna fail dis c2 exam..
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    (Original post by macccj)
    it looks like a quadratic - factorise into (sin^2 x + cos^2 x) (sin^2 x + cos^2 x) (ie, it's squared)

    also sin^2 x + cos^2 x = 1 (pythagoras)

    so it's effectively 1 squared = 1 hope it helps!
    ohhhhhhhhhhhh okkk i got ittttt thxxxxxxxxxxx
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    (Original post by tfdes)
    Simplify:

    cos4x + 2sin2xcos2x + sin4x
    nty
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    hahaha, sure? it's just one of those funny rule things
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    also, how do you make the square-power appear there, instead of typing ^2..?
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    (Original post by macccj)
    also, how do you make the square-power appear there, instead of typing ^2..?
    u type [ sup ] x [ / sup ]
    and for A2 u do [ sub ] x [ / sub ]
    (wit no spaces in bwtween)
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    (Original post by macccj)
    also, how do you make the square-power appear there, instead of typing ^2..?

    (Original post by tfdes)
    u type [ sup ] x [ / sup ]
    and for A2 u do [ sub ] x [ / sub ]
    (wit no spaces in bwtween)
    Alternatively, use LaTeX (see post here: http://www.thestudentroom.co.uk/wiki/LaTex ) which gives even neater results.

    e.g. \dfrac{4x+3}{3x^{6}}
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    Thank you!!
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    (Original post by tfdes)
    Simplify:

    cos4x + 2sin2xcos2x + sin4x
    cosx=u, sinx=v

    v^2+2uv+u^2 is obviously (v+u)^2

    so your equation is (cosx+sinx)^2
 
 
 
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