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    ive done the first part of this question and found that the roots of an equation are

    -1+/- rt2

    one of these is tan 22.5 (-1+rt2)

    then the next part says to express the other root in trigometric form and i dont get it!!

    thanks
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    (Original post by sarah12345)
    ive done the first part of this question and found that the roots of an equation are

    -1+/- rt2

    one of these is tan 22.5 (-1+rt2)

    then the next part says to express the other root in trigometric form and i dont get it!!

    thanks
    let a = -1 + rt2, b = - 1 - rt2, @ = 22.5

    Note ab = -1 by difference of squares and a = [email protected]

    so b = -1/[email protected] = cot([email protected]) = tan(pi/[email protected])

    how do they want it in trig form? there are lots of ways of writing it?

    probably would help if you wrote out the whole question
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    the question is write out the formula for tan 2x. deduce that tan 22.5 is a root of the equation t^2+2t-1+0 and hence find the exact value of tan 22.5
    express the other root of the quadratic in trigometrical form
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    (Original post by sarah12345)
    the question is write out the formula for tan 2x. deduce that tan 22.5 is a root of the equation t^2+2t-1+0 and hence find the exact value of tan 22.5
    express the other root of the quadratic in trigometrical form
    Well they could be asking for [email protected] or tan(pi/[email protected]) I guess either is right as they're not specific
 
 
 
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