angle between lines (2 Viewers)

[kr73114]

how do you find the obtuse angle between two lines when given 2 equations

 

[ohexploitable]

180 - acute angle

 

[hungwell1337]

do you know how to find the acute angle?

 

[kr73114]

yeh i know how to find acute angle
m1-m2/1+m1m2

 

[kr73114]

180 - acute angle

for half my answers its right and for the other half its wrong
is that just my own silly mistake? or is there an exception for this rule?

 

[Shikobe]

tan@=(M1-M2)/(1+M1M2), remember to absolute the expression on the right.
But in our case we want the obtuse so we dont necessarily need to take the absolute, and yea...if your angle you found is obtuse then just leave it, dont minus it from 180...other than that i dont know whats wrong...