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Please solve as soon as possible. lf a line makes an angle of tan^-1(-1/√3) with x axis and passes through the points (-p, -2√3) and (4, -1) find the value of p.​

User Lgmccracken
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1 Answer

12 votes
12 votes

Answer:
p = -10+√(3)

When writing this on a keyboard, we could say p = -10+sqrt(3)

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Step-by-step explanation:

We're told the angle between the line and x axis is
\tan^(-1)\left((-1)/(√(3))\right)

This is one of the infinitely many exact solutions to the equation
\tan(\theta) = (-1)/(√(3)) where
\theta (Greek letter theta) is the angle in question.

It turns out that the tangent ratio is exactly the slope of a line.

  • slope = rise/run
  • tan(angle) = opposite/adjacent

Both describe a ratio of how far something moves up or down, over how far it moves to the right.

So saying
\tan(\theta) = (-1)/(√(3)) means that the slope of our mystery line is exactly
(-1)/(√(3))

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What we'll do is compute the slope on the points
(\ -p, -2√(3) \ ) \text{ and } (4, -1)

That produces some algebraic expression in terms of p. That expression is set equal to the previously mentioned slope of
(-1)/(√(3)) which will allow us to solve for p.

Part 1


m = \text{slope}\\\\m = (y_2-y_1)/(x_2-x_1)\\\\m = (-1-(-2√(3)))/(4-(-p))\\\\m = (-1+2√(3))/(4+p)\\\\-(1)/(√(3)) = (-1+2√(3))/(4+p) \ \ \text{ ... plug in the previously mentioned slope}\\\\-(4+p) = (√(3))(-1+2√(3)) \ \ \text{ ... cross multiply}\\\\

Part 2


-4-p = -√(3)+2(√(3))^2\\\\-4-p = -√(3)+2(3)\\\\-4-p = -√(3)+6\\\\-p = -√(3)+6+4\\\\-p = 10-√(3)\\\\p = -10+√(3)\\\\

User Claas Bontus
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3.4k points