Posted by **dan** on Wednesday, January 23, 2013 at 9:47pm.

cos 17pi/6 + tan 17pi/6

- Trigonometry -
**Reiny**, Wednesday, January 23, 2013 at 10:27pm
Perhaps you might find it easier to think in degrees ?

17π/6 radians = 510°

which is coterminal with 150°

cos 150° = - cos30° = -√3/2 , by CAST rule

tan 150 = - tan30 = -1/√3

so cos 17π/6 + tan 17π/6

= -√3/2 - 1√3 , but 1/√3 = √3/3

= -√3/2 - √3/3

= ( -3√3 - 2√3)/6 = -5√3/6

## Answer this Question

## Related Questions

- Trigonometry - Checking my work - Find the sum of the three smallest positive ...
- Math(Please check!!!) - 1) Evaluate (if possible) the sine, cosine, and tangent ...
- Pre-cal (Please Check) - 1) Evaluate (if possible) the sine, cosine, and ...
- trig - Find the exact value. Without using a calculator a) cos (-17pi/6) b) sec...
- math - if A (2, -1) and B (4,7) are endpoints of a diameter of a circle, what is...
- Calculus help please - I have to evaluate the following: tan((sin^-1)(2/7)) and ...
- Trigonometry desperate help, clueless girl here - 2. solve cos 2x-3sin x cos 2x...
- Trigonometry - 1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two ...
- trig - Find exact value of the expression. sin( 27pi/4 + 17pi/6)
- Trigonometry - Please review and tell me if i did something wrong. Find the ...

More Related Questions