PowerXtremeBaby
New member
- Joined
- Aug 2, 2009
- Messages
- 7
My trig class is using a book that hasn't been published yet, we're the first class to use it and it is totally unhelpful.
Use even-odd identities to solve each equation. Find all solutions over the interval [0,2pi]. Verify your solutions by graphing.
1) Tan(-x)= -2.5
I got as far as:
-sinx/cosx=-2.5
and now i'm stuck.
I know the identity is tan(-x)=-tan(x), but I don't know how to use that to help me.
2) 2.4= (cos(-x)/2)+1
I don't even know where to start.
Identity is cos(-x)=cos(x)?
3) 2(sin(-x)/tanx)=0.8
So far I have 2(sin(-x)/(sin(x)/cos(x))=0.8
and then I flipped the bottom fraction and multiplied:
2(sin9-x)X(cos(x)/sin(x)=0.8
I know the sins can cancel, but I forget how to do it where one is negative and one is positive.
and I don't understand what it wants as the answer.
I'm completely lost! My professor doesn't seem to understand what he is trying to teach, so I don't understand it.
Use even-odd identities to solve each equation. Find all solutions over the interval [0,2pi]. Verify your solutions by graphing.
1) Tan(-x)= -2.5
I got as far as:
-sinx/cosx=-2.5
and now i'm stuck.
I know the identity is tan(-x)=-tan(x), but I don't know how to use that to help me.
2) 2.4= (cos(-x)/2)+1
I don't even know where to start.
Identity is cos(-x)=cos(x)?
3) 2(sin(-x)/tanx)=0.8
So far I have 2(sin(-x)/(sin(x)/cos(x))=0.8
and then I flipped the bottom fraction and multiplied:
2(sin9-x)X(cos(x)/sin(x)=0.8
I know the sins can cancel, but I forget how to do it where one is negative and one is positive.
and I don't understand what it wants as the answer.
I'm completely lost! My professor doesn't seem to understand what he is trying to teach, so I don't understand it.