Photo AI

The point A (−6, 4) and the point B (8, −3) lie on the line L - Edexcel - A-Level Maths Pure - Question 6 - 2008 - Paper 2

Question icon

Question 6

The-point-A-(−6,-4)-and-the-point-B-(8,-−3)-lie-on-the-line-L-Edexcel-A-Level Maths Pure-Question 6-2008-Paper 2.png

The point A (−6, 4) and the point B (8, −3) lie on the line L. (a) Find an equation for L in the form ax + by + c = 0, where a, b and c are integers. (b) Find the ... show full transcript

Worked Solution & Example Answer:The point A (−6, 4) and the point B (8, −3) lie on the line L - Edexcel - A-Level Maths Pure - Question 6 - 2008 - Paper 2

Step 1

Find an equation for L in the form ax + by + c = 0, where a, b and c are integers.

96%

114 rated

Answer

To find the equation of the line L, we first calculate the slope (m) using the points A and B:

m=y2y1x2x1=348(6)=714=12m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{-3 - 4}{8 - (-6)} = \frac{-7}{14} = -\frac{1}{2}

Now, we can use the point-slope form of the line equation:

yy1=m(xx1)y - y_1 = m(x - x_1)

Using point A (−6, 4):

y4=12(x+6)y - 4 = -\frac{1}{2}(x + 6)
y4=12x3y - 4 = -\frac{1}{2}x - 3
y=12x+1y = -\frac{1}{2}x + 1

To convert to the form ax + by + c = 0:

12x+y1=0\frac{1}{2}x + y - 1 = 0

Multiplying through by 2 to eliminate the fraction:

x+2y2=0x + 2y - 2 = 0

Thus, the equation is:

x+2y2=0x + 2y - 2 = 0

Step 2

Find the distance AB, giving your answer in the form k√5, where k is an integer.

99%

104 rated

Answer

To find the distance AB between the points A (−6, 4) and B (8, −3), we use the distance formula:

d=(x2x1)2+(y2y1)2d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

Substituting the coordinates of points A and B:

d=(8(6))2+(34)2d = \sqrt{(8 - (-6))^2 + (-3 - 4)^2}
=(8+6)2+(7)2= \sqrt{(8 + 6)^2 + (-7)^2}
=(14)2+(7)2= \sqrt{(14)^2 + (-7)^2}
=196+49= \sqrt{196 + 49}
=245= \sqrt{245}
=49×5= \sqrt{49 \times 5}
=75= 7\sqrt{5}

Thus, the distance AB is:

k5k\sqrt{5} where k=7k = 7.

Join the A-Level students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;