help | Mathematics | Page 1

astral flax Dec 22, 2024, 6:38 PM

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reef sandalBOT Dec 22, 2024, 6:38 PM

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astral flax

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thin umbra Dec 22, 2024, 6:42 PM

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astral flax

Do you know the exponential form of a complex number ? If not then multiply the denominator and numerator by cos(9x)+isin(9x) develop and think of some trig identities

neon lily Dec 22, 2024, 6:42 PM

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can you recognixe eulers formula?

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astral flax Dec 22, 2024, 7:09 PM

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thin umbra Do you know the exponential form of a complex number ? If not then multiply the ...

idk that form

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i tried that method and i get cos(7x)+i sin(11x)

hardy wigeon Dec 22, 2024, 7:21 PM

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astral flax i tried that method and i get cos(7x)+i sin(11x)

show your work

astral flax Dec 22, 2024, 7:22 PM

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hardy wigeon show your work

i get cos2xcos9x - sin2xsin9x + i(sin2xcos9x + cos2xsin9x)

then cos(2x-9x) and sin(2x+9x)

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then cos(-7x) is cos(7x) and sin(11x)

hardy wigeon Dec 22, 2024, 7:22 PM

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ah.

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@astral flax do you know the angle addition formula for cosine?

astral flax Dec 22, 2024, 7:24 PM

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i use cos(a-b) = cosacosb + sinasinb

hardy wigeon Dec 22, 2024, 7:25 PM

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astral flax i use cos(a-b) = cosacosb + sinasinb

addition

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cos(a+b)

astral flax Dec 22, 2024, 7:25 PM

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hardy wigeon cos(a+b)

oh i switch negative sign?

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cosacosb - sinasinb

hardy wigeon Dec 22, 2024, 7:26 PM

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astral flax cosacosb - sinasinb

so what form is your real part in your working?

astral flax Dec 22, 2024, 7:26 PM

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OHHHH

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thank you i got it sir

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+close

wraith belfryBOT Dec 22, 2024, 7:26 PM

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astral flax +close

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wraith belfryBOT Dec 22, 2024, 7:26 PM

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wraith belfry

Thank you for your feedback! dark matter has been awarded 1 helper_points . They now have 908 . They have 0 daily left for today.

wraith belfryBOT Dec 22, 2024, 7:26 PM

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wraith belfry

the_homie._. Thank you for helping our users, however our Mathematics Team cares about the health of its members, so you can no longer receive helper_points since you surpassed your daily limit, but don't worry, it will be reset tomorrow.