## IB Maths HL Vectors, perpendicular

Discussions for the Core part of the syllabus. Algebra, Functions and equations, Circular functions and trigonometry, Vectors, Statistics and probability, Calculus. IB Maths HL Revision Notes

### IB Maths HL Vectors, perpendicular

IB Mathematics HL – Vectors, Scalar Product, perpendicular vectors

How can we find the value of the parameter c for which the vectors $a= \begin{pmatrix} c \\ 2c \\ 4 \end{pmatrix}$ and $b= \begin{pmatrix} 3 \\ -2 \\ 5 \end{pmatrix}$ are perpendicular?

Thanks
elizabeth

Posts: 0
Joined: Mon Jan 28, 2013 8:09 pm

### Re: IB Maths HL Vectors, perpendicular

IB Mathematics HL – Vectors, dot Product, perpendicular vectors

We know that two vectors are perpendicular if and only their dot product equals zero.

Therefore

$a \cdot b=(c \cdot 3) + (2c \cdot (-2)) + (4 \cdot 5) =3c- 4c+20=0$

$\Rightarrow c= 20$

Hope these help!
miranda

Posts: 268
Joined: Mon Jan 28, 2013 8:03 pm

### IB Mathematics HL Vectors, perpendicular

Thanks miranda!!
elizabeth

Posts: 0
Joined: Mon Jan 28, 2013 8:09 pm