Define :
Direction angles of a straight line,

Define : Direction cosines of a straight line,

Define : Direction ratios of a straight line.

If alpha, beta, gamma be the direction angles of a straight line, then prove that sin^(2) alpha+sin^(2) beta+sin^(2) gamma =2

The direction angles of a straight line are 30^(@), 60^(@) and 150^(@) . Is the statement true?

Find the direction cosines of a straight line which is situate on yz-plane and inclined at an angle 60^@ with poistive direction of z-axis.

The direction agnles of a straight line are 120^@,45^@,30^@ . Is the statement true? Give reason.

Find the direction ratios of a straight line which makes equal angles with the coordinate axes. How many such straight line are there?

Can the numbers 1, 2, 3 be the direction cosines of a straight line?

Let l_(1), m_(1), n_(1) and l_(2), m_(2), n_(2) be the direction ratios of two given straight lines. Find the direction ratios of a straight line which is perpendicular to both the given straight lines.

Can the numbers 1/2, -1/sqrt(2), 1/2 be the direction cosines of a straight line?