- #1

concon

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- 0

## Homework Statement

Determine for what value/s of the parameter a the following planes in R3 are perpendicular:

ax + 0y - 5z = 3

ax + ay + 5z = -26

Write answer in form {a,b} or {a}

## Homework Equations

I know that in R2 two vectors are perpendicular if

u*v = 0

What what do I use for R3 with planes?

## The Attempt at a Solution

To solve this problem I need to know what it means for two planes to be perpendicular. I know in R2 that means there dot product is zero, what does that mean in R3? Also dot product?