1. ## Trig Equation

Is there a way to get a exact value to 15 = tan(3x) ?

If there isn't I will post the original equation whereby I reached it, and perhaps there is a way.

2. tan 3x=15
3x=tan^-1(15)
x=[tan^-1(15)]/3
x=28.72864172

3. Originally Posted by classicstrings
Is there a way to get a exact value to 15 = tan(3x) ?

If there isn't I will post the original equation whereby I reached it, and perhaps there is a way.
Please post the original equation as I can't see how to get the exact value.

@alinailiescu

It asks for exact value, In the UK, this usually means no calculators can be used.

4. Than you shoul stop at this step. Note that tan^-1 is the invers function of tan. Noted also arctan or atan, to avoid confusion with 1/tanx=(tanx)^-1
tan 3x=15
3x=tan^-1(15)
x=[tan^-1(15)]/3

5. Well here it is:

5(-0.2e^(-0.2x)sin(3x) + e^(-0.2x)3cos(3x)) = 0