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Question
Find distance CD where C(– 3a, a), D(a, – 2a)
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Solution
Let C(x1, y1) and D(x2, y2) be the given points
∴ x1 = – 3a, y1 = a, x2 = a, y2 = – 2a
By distance formula,
d(C, D) = `sqrt((x_2 - x_1)^2 + (y_2 - y_1)^2`
= `sqrt(["a" - (-3"a")]^2 + (-2"a" - "a")^2`
= `sqrt(("a" + 3"a")^2 + (-2"a" - "a")^2`
= `sqrt((4"a")^2 + (-3"a")^2`
= `sqrt(16"a"^2 + 9"a"^2)`
= `sqrt(25"a"^2)`
∴ d(C, D) = 5a units
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