- #1

HaniZaheer

- 4

- 0

If neither x nor y is zero, then by x · y = | x | | y | cos θ,

|x · y|=| x | | y | cos θ | ≤ | x | | y |

since -1 ≤ cos θ ≤ 1

How valid is this a proof of the Cauchy-Schwarz inequality?