OK so i still need help before my test

[rommel902]

so tangent (2u) - cotanget (u) = 0 in radians and interval [0, 2pi]

that equation goes to sine (2u) / cosine (2u) = cosine (u) / sin (u)

that goes to [ 2sin(u)cos(u) / 1 - 2sin^2(u) ] = cos (u) / sin (u)

how do i solve it?

Please i have a test to take!!
Thanks

 

[Gene]

Good start. Multiply both sides by
sin(u)/cos(u). Then by
1-2sin²(u) Then add
2sin²(u) to both sides.
Can you take it from there?

 

[rommel902]

Thanks gene

but so 2sin^2(u) + 2sin^2(u) = 1 how do i solve it?

 

[stapel]

I'm glad to see that you figured out my earlier advice and have taken a few steps toward the solution.

There are probably many ways to approach this equation, but I would start by moving the cotangent to the other side of the equation, and then converting everything to sines and cosines. Then apply the double-angle formulas, and simplify from there.

Please post further replies to either this or the other thread for this exercise, but not to both.

Thank you.

Eliz.

 

[Gene]

Surely you jest.
4sin²(u)=1
Anyone who got this far can finish that :evil: