# A line AB in three dimensional space makes angles 45° and 120° with the positive x – axis and the positive y – axis respectively. If AB makes an acute angle ? with the positive z – axis, then ? equals -

SHAIK AASIF AHAMED
7 years ago
Hello student,
Thanks and regards
Shaik Aasif
SHAIK AASIF AHAMED
7 years ago
Hello student,
Directional cosines of line segment AB is cos 45,cos 120,cos$\Theta$
so cos245+cos2120+cos2$\Theta$=1
we get cos$\Theta$=1/2
so$\Theta$=60 degrees.
Thanks and regards
Shaik Aasif