Question 871913
How do you find the exact value of 
tan 285=tan(45+240)=tan(45)+tan(240)/(1-tan(45)*tan(240))=(1+√3)/(1-√3)
Check with calculator:
tan285˚≈-3.7320…
Exact value=(1+√3)/(1-√3)≈-3.7320…