Preliminary 2U Maths Question (1 Viewer)

LC14199 · Aug 23, 2015

hey guys, this is a particular type of question. I don't really know how to go about solving questions that mention an angle.

Example:
Find the gradient of the straight line:
i) Perpendicular to the line making an angle of 120 degrees with the x-axis in the positive direction

Can someone simply explain how this works? All the other questions involving this I have no issues with, but if it mentions making an angle, I get stumped.

Cheers

LC

InteGrand · Aug 23, 2015

LC14199 said:
hey guys, this is a particular type of question. I don't really know how to go about solving questions that mention an angle.

Example:
Find the gradient of the straight line:
i) Perpendicular to the line making an angle of 120 degrees with the x-axis in the positive direction

Can someone simply explain how this works? All the other questions involving this I have no issues with, but if it mentions making an angle, I get stumped.

Cheers
LC

$The line making an angle of $120^\circ$ to the positive $x$-axis has slope $m = \tan (120^\circ) = -\sqrt{3}$. So the slope of the required line is $-\frac{1}{-\sqrt{3}}=\frac{1}{\sqrt{3}}$.$

$(Using the fact that a line making angle $\theta$ with the positive $x$-axis has slope $m=\tan \theta$, which you are expected to know.)$

LC14199 · Aug 23, 2015

I recognise that rule, I actually forgot about it ahaha, cheers

Preliminary 2U Maths Question (1 Viewer)

LC14199

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InteGrand

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