Let BC be a line segment on which D, E are two points such that BE > BD and BC · DE = BD · CE. A is any other point not on the line BC then prove that BE subtends a right angle at A if AE bisects the angle DAC.

A body is rotating with an angular velocity of 2radians per second about the line joining (1, 2,3) and (2, 3,5) find the velocity of the particle of the body which is momentarily at (3, 5,6)

Show that: vectorPQ+vectorPR+ vectorPS +vectorTP+vectorUP = 4PQVector

Given that A×(B×C) = (A.C)B - ( A.B)C , deduce that (A×B)×C = (A.C)B - (B.C)A

the mean of 30 observations was 17 with sd2. later it was found that two of the observations were incorrect, which were recorded as 19vand 21.find the correct sd if the incorrect values are deleted and correct values 22 and 15 are included

Find the component of 2i +3j +k in the direction of 3i-j