co - variance 問題

你應該要用 c = diag { 0.0052 ( 5 / 206265 )2 }
a 同 b 都係 ( 2 x 1 ) matrix
然後就係
co-variance = a T c b
姐係 co-variance = ( 1 x 2 )( 2 x 2 )( 2 x 1)
答案係 : 1 x 1 vector~

AB 係 係用機器 measure 出來的數字,是有 measurement error 的
我都唔係好知應該點講
不如我打條Question出來

2008-05-04 20:31:14 補充：
in the following fifgure a total station was placed at point A and measured the distance and vertical angle to target B. The measured distance is 400 m with a standard deviation of 5 mm, and the measured vertical angle is 30 degree with a standard deviation od 5 seconds.

2008-05-04 20:31:23 補充：
From the measurement the horizontal distance , D , and the heu+ight difference, h , between point A & B are computed.
Estimate the variances of the computed D & h and their covariance.

2008-05-05 10:43:34 補充：
係independent

相信問題冇咁簡單，你講
斜線AB = 400 米 ( with a standard deviation of 5 毫米 )
冇講到distribution，AB是normally distributed? uniform?
AC = AB cos (角BAC), cos一個random variable既distribution係？
AB同角BAC既distribution係唔係independent?
呢d資料都好關鍵。

計Covariance首先要知道Joint distribution，計到先算啦。