[sahill]

This may be a typo, but if not, is this solvable?
1-cot^2theta=?

[CroCivic91]

1-cot^2theta = ?
It is kind of important what you want this expression to be equal to...
Lets assume you want it to be equal to 0...

1-cot^2theta = 0 is equal to (1-cot(theta))*(1+cot(theta)) = 0
Now, 2 numbers multiplied can produce 0 only if one (or both) of them are equal to 0.

So, first lets assume that 1-cot(theta)=0
That means that cot(theta) = 1 and that means that theta = pi/4 rad + k*pi, for any natural k

Now, lets assume that 1+cot(theta)=0
That means that cot(theta)=-1 and that means that theta = -pi/4 + k*pi, for any natural k

Kresho

[Glipto]

Hmmm... is not an ecuation.

I think...

Cos^2 theta + Sin^2 theta = 1 (Pitagoras)

1 - Cos^2 theta = Sin^2 theta

[CroCivic91]

I would agree with you, but his original post said:

1-cot^2theta=?

cot != cos

[reinsuranc]

sin^2theta + cos^2theta = 1

divide both sides by sin^2theta:

(sin^2theta)/(sin^2theta) + (cos^2theta)/(sin^2theta) = 1/sin^2theta

1 + cot^2theta = csc^2theta

[Glipto]

OOPS!! I NEED GLASSES!!

I agree with Reinsuranc, if the sign is positive the identity is beautiful.

[MathMaven53]

1- cot^2 t = 1 - cos^2 t/sin^2 t

= (sin^2 t - cos^2 t)/sin^2 t

= - cos 2t/sin^2 t


Note that cos^2 t - sin^2 t = cos 2t

2sin^2 t = 1 - cos 2t

1- cot^2 t = - cos 2t/sin^2 t

= (-2 cos 2t)/(2sin^2 t

= (-2 cos 2t)/(1 - cos 2t)

[sammay_mon]

Hay I'm new to this
Do I ask a "?" and someone'll help me?