a straight line has the equation x-2y+4=0
what angle does the line make with x+3y=0

Question

a straight line has the equation x-2y+4=0
what angle does the line make with x+3y=0

amistre64 · Answer

if you can compare slope, that would be useful to a solution

amistre64 · Answer

|dw:1348937031519:dw|

$$cos(a)=\frac{a.b}{|a||b|}$$

amistre64 · Answer

prolly shouldnt of used an a for different things in that should i

anonymous · Answer

tan(a) = slope of first line
tan(b) = slope of second line
|a - b| = angle between them

amistre64 · Answer

$$cos(a)=\frac{m_1.m_2}{|m_1||m_2|}$$

thats better :)

anonymous · Answer

You can use arctan to figure this out. Drawing the lines out and the corresponding triangles should help you visualize the problem.

amistre64 · Answer

the russians method is quite elegant as well

anonymous · Answer

I just love when someone asks a question and then never responds

anonymous · Answer

a-b formula is not working
I found the slopes but I don't know after that

anonymous · Answer

one you find the slopes, 
take the arctan of of each and subtract them