Find the equation of a line: i) whose inclination is 45° and y intercept is 5.
ii) with inclination = 60° and passing through (-2,5). iii) passing
points (-3,1) and (1,5).
Answers
Step-by-step explanation:
(1.) inclination = 45°
∴ slope ( m ) = tan 45°
m = 1;
y intercept ( c ) = 5
equation :
y = mx + c
y = 1.x + 5
y = x + 5; ..............(1)
(2.) passing through point = (-2, 5)
inclination = 60°
∴ m = tan 60°
m = √3
equation:
( x - x1 )m = ( y - y1 )
( x - (-2) )√3 = ( y - 5 )
( x + 2 )√3 = ( y - 5 )
√3x + 2√3 = y - 5
√3x = y - 5 - 2√3
x = y - 5 - 2√3 / √3
x - y + 5 = -2√3 / √3
x - y = -2 - 5
x - y = -7 .........(2)
(3.) points :
(x1 , y1) = (-3, 1)
(x2, y2) = (1, 5)
m = y2 - y1 / x2 - x1
= 5 - 1 / 1 - (-3)
= 4 / 4
= 1
∴ m = 1;
equation :
( x - x1 )m = ( y - y1 )
( x - 1 ).1 = (y - 5)
x - 1 = y - 5
x + y = 1 - 5
x + y = -4 ...............(3)
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