VITEEE 2010 Paper

A (-2,1), B (2,3) and C (-2,-4) are three given points.
Slope of the line BA
m1=

1−3

−2−2

=

1

2

[Using‌slope‌formula,m=

y2−y1

x2−x1

]
Slope of the line BC
m2=

−4−3

−2−2

=

7

4

Now, angle between AB and BC is given by
tan‌θ=|

m1−m2

1+m1m2

|=|

1 2 − 7 4

1+ 1 2 . 7 4

|
⇒ tan‌θ=|−

10

15

|
⇒ tan‌θ=|−

2

3

|
⇒ θ=tan−1|−

2

3

|
⇒ θ=tan−1(

2

3

)‌‌‌‌‌‌‌‌[∵|−x|=x]