Tan[arctan(2/3) + arccos(8/17)]

[jrjack]

Homework Statement

tan[arctan(2/3)+arccos(8/17)]

Homework Equations

tan(u+v)=$\frac{\tan u+\tan v}{1-\tan u\tan v}$

The Attempt at a Solution

After drawing 2 triangles for arctan and arccos (both in Quadrant 1), and inserting them into the addition formula for tan, I get:
$$\frac{\frac{2}{3}+\frac{15}{8}}{1-\frac{2}{3}(\frac{15}{8})}$$
is that right?
if so, then maybe my math is off...
I got the numerator reduced to 23/8
and denominator of -1/4
for a total of -23/3 ...but that's not correct.

 

[Dick]

I think your math with the fractions is off. 2/3+15/8 is not equal to 23/8. Can you show why you think it is?

 

[jrjack]

Sorry, mis-typed...I meant 23/12

2/3 =16/24
15/8=30/24******Found my problem, this should be 45/24


Thanks for looking at this, I knew it had to be something simple...I need to slow down.