Hello, this is a question from a pure mathematics textbook:(adsbygoogle = window.adsbygoogle || []).push({});

(2D vectors)

The vectorsaandbare of equal magnitute k (k does not equal 0), and the angle between a and b is 60 degrees. Ifc=3a-bandd=2a-10b

A) Show thatcanddare perpendicular vectors.

(Sadler, A.J., Thorning, D.W.S (2007, pg.63). Understanding Pure Mathematics, Glasgow: Oxford Universty Press).

c.d=0

=|c||d|cos(90)

Therefore, c.d/|c||d|=cos(90)

'Normally' for the dot product, the coefficients of the 'i' component of the two vectors are multiplied togeather, and the same process is applied to the j components, then they are added togeather.

I would attempt the question, but to be honest I'm not sure what steps to take; since my base vectorsaandbare not orthogonal. Am I using the correct method? An answer would be much appreciated, I apologise for the language used and the presentation, I hope its accurate.

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# Homework Help: Proving perpendicular vectors

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