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# Double Angle Formulas help watch

1. Hey,

Show that:

tanx + cotx = 2cosec2x

But the = is three lines (no button on the keyboard).

Cheers
2. Write the LHS out in terms of sin and cos, and then put it over a common denominator
i.e. a/b + b/a = (a^+b^2) /(ab)

3. Those three lines mean it is always equal to. Try turning cosec(2x) in something with only x (not 2x), using the sin double angle formula.
4. (Original post by TheDuck)
Write the LHS out in terms of sin and cos, and then put it over a common denominator
i.e. a/b + b/a = (a^+b^2) /(ab)

Thanks, but it's: sinx/cosx + 1/tanx

To get it in terms of sin/cos would I put the second part as 1/(sinx/cosx)? Not sure how that would work
5. (Original post by Waheyyyy)
Thanks, but it's: sinx/cosx + 1/tanx

To get it in terms of sin/cos would I put the second part as 1/(sinx/cosx)? Not sure how that would work
yes thats correct ... so its cos/sin... multiply through and then ull get ur answer

6. edit: darkness, you beat me to it. Damn you, LaTeX!

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Updated: November 10, 2008
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