Question

The obtuse angle between the lines y = -2 and y = x +2 is

Answer 1

Given : Two lines

y = -2 and y = x +2

To Find :

Angle between these two lines

Solution :

•Equation of straight line is of the form y = mx + c

where , m = slope of line

•line 1 :

y = -2

y = mx + c

By comparing we get,

slope of line is 0

m1 = 0

• line 2 :

y = x +2

y = mx + c

BY comparing we get ,

slope of line is 1

m2 = 1

•If angle between two lines of slope m1 & m2 is A

then tan A = | [ (m2-m1)/(1+m1m2) ] |

tan A = | (1-0)/(1+(1)(0) ) |

tan A = | 1 | = 1 or -1

•Since A is obtuse angle

=> tan A = -1

=> A = tan^-¹ ( -1)

=> A = 3π/4

•Hence obtuse angle between the given lines is 3π/4