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suminha
The answer of this question is y=(b/a)(x-2c).
But I have no idea how to approach this question... can someone help me please???
Thank you in advance!

Posted from my mobile device


Solution:

Equation of line A give is ax+by=c
=> y=-a/bx +c/a (rewriting in y=mx+c form)

For perpendicular line, product of slope is -1
=>m1 * m2 = -1
=> -a/b * m2 = -1
=> m2 = b/a

Equation of line M will be,
=> y = b/a x + k

As line M passes from (2c,0), substitute this points in line M equation,
=> 0 = b/a * 2c + k
=> k = -2bc/a

Equation of line M,
=> y = b/a x -2bc/a
=>y = b/a (x-2c) or
=> ay=bx-2bc => bx-ay-2bc=o.

Feel free to post your queries, in case you have any question.
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suminha
The answer of this question is y=(b/a)(x-2c).
But I have no idea how to approach this question... can someone help me please???
Thank you in advance!

Posted from my mobile device


Solution:

Equation of line A give is ax+by+k =0
=> y=-a/bx +k/a (rewriting in y=mx+c form)

For perpendicular line, product of slope is -1
=>m1 * m2 = -1
=> -a/b * m2 = -1
=> m2 = b/a

Equation of line M will be,
=> y = b/a x + k

As line M passes from (2c,0), substitute this points in line M equation,
=> 0 = b/a * 2c + k
=> k = -2bc/a

Equation of line M,
=> y = b/a x -2bc/a
=>y = b/a (x-2c) or
=> ay=bx-2bc => bx-ay-2bc=o.

Feel free to post your queries, in case you have any question.

Thank you for helping me!
However, I don’t understand why you wrote “Equation of line A give is ax+by+k =0” instead of ax+by=c -> ax+by-c=0..
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suminha
kush09
suminha
The answer of this question is y=(b/a)(x-2c).
But I have no idea how to approach this question... can someone help me please???
Thank you in advance!

Posted from my mobile device


Solution:

Equation of line A give is ax+by+k =0
=> y=-a/bx +k/a (rewriting in y=mx+c form)

For perpendicular line, product of slope is -1
=>m1 * m2 = -1
=> -a/b * m2 = -1
=> m2 = b/a

Equation of line M will be,
=> y = b/a x + k

As line M passes from (2c,0), substitute this points in line M equation,
=> 0 = b/a * 2c + k
=> k = -2bc/a

Equation of line M,
=> y = b/a x -2bc/a
=>y = b/a (x-2c) or
=> ay=bx-2bc => bx-ay-2bc=o.

Feel free to post your queries, in case you have any question.

Thank you for helping me!
However, I don’t understand why you wrote “Equation of line A give is ax+by+k =0” instead of ax+by=c -> ax+by-c=0..

That was a typo, I have corrected now.
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suminha
Line A, of which equation is ax+by=c, is perpendicular to line M passing through (2c,0). What is the equation of line M in terms of a, b and c?

Here, ax = by = c
or, by = - ax + c
y = - a/b x + c/b

Comparing to the form y = mx + c

The slope say, m a = - a/b

Since the lines are perpendicular,
m a * m m = -1
Therefore, - a/b * m m = -1
Or m m = b/a

Also, we know the line passes through (2c,0). That is when x = 2c, y = 0
Therefore, y = mx + c becomes,
0 = b/a * 2c + c m
or, c m = - [2bc][/a]

Again substituting the value in y = mx + c
You get,
y = b/a * x - 2bc/a

---------
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Step 1 : Equation of line parallel to ax + by + c = 0 is bx - ay + k = 0 , note here c and k are constants.

So we got equation of M : bx - ay + k = 0

Step 2 : Substitute (2c, 0) in M, we get k = -2bc.

Step 3 : Writing final equation : bx - ay -2bc = 0
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