Trig help needed before i take test asap!!!!

[rommel902]

tan 2u - cot u = 0 i need to know how that is solved


and one other (a^2)-(a^4)= ?

sorry feel stupid for asking btu please help me before my test
PLEase!!!!!!

 

[stapel]

1) tan 2u - cot u = 0

Is this "tan(2x) - cot(u) = 0", or "tan²(u) - cot(u) = 0", or something else? Are you in degrees or radians? Are you solving in general, or over some specified interval?

2) (a^2)-(a^4)= ?

Without a value for "a", there is no way to find a value for the expression. Or were the instructions something other than "evaluate"?

Please reply with clarification, including the steps you have tried thus far.

Thank you.

Eliz.

 

[rommel902]

tan (2u) - cot (u) = 0 [0, 2pie] in radians

 

[stapel]

Note: A "pie" is a dessert pastry; on the other hand, "pi" is a number.

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.

Eliz.

 

[rommel902]

sorry so what do you mean by move the cotangent to the other side

 

[stapel]

sorry so what do you mean by move the cotangent to the other side

Add "cot(u)" to both sides of the equation.

Eliz.

 

[rommel902]

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

 

[stapel]

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

How did you get to this stage? Please reply showing your steps.

A good next step would be to add the "like" terms on the left-hand side. (Hint: 2 + 2 = 4.) Then follow the usual "by square roots" procedure for solving quadratics of this form.

Eliz.