1800-150-456-789
FlagBACK
Flag Vectors> angle between diagonals of a parallelogra...
question mark

angle between diagonals of a parallelogram whose side represented by vector a =2i +j +k and vector b = i -j - k. Options are A) cos^-1 (1/3) B) cos^-1 (1/2) C) cos^-1 (4/9) D) cos^-1 (5/9)

ayush Sharma , 7 Years ago
Grade 11
anser 2 Answers
Shailendra Kumar Sharma

Last Activity: 7 Years ago

Cos(Theta) =A.B./ABSo the angle will be Cos (Theta) = (​2i +j +k). (i -j - k) /( \sqrt{4+1+1})*\sqrt{(1+1+1))}\Theta =(2-1-1)/\sqrt{6} X\sqrt{3}) =0So the angle is 90 Degree as cos 90 is zero

Subham

Last Activity: 5 Years ago

We can find digonal vector a+b and a-b by this we can use formula cos theta equals to (a-b)(a+b)/|a+b||a-b| we got cos theta equals to 1/3

Provide a better Answer & Earn Cool Goodies

star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Other Related Questions on vectors

question mark
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) 
 
vectors
0 Answer Available

Last Activity: 3 Years ago

question mark
Show that: vectorPQ+vectorPR+ vectorPS +vectorTP+vectorUP = 4PQ
Vector
vectors
0 Answer Available

Last Activity: 3 Years ago

question mark
Given that A×(B×C) = (A.C)B - ( A.B)C , deduce that (A×B)×C = (A.C)B - (B.C)A
vectors
0 Answer Available

Last Activity: 3 Years ago

question mark
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
vectors
0 Answer Available

Last Activity: 3 Years ago

question mark
Find the component of 2i +3j +k in the direction of 3i-j 
 
vectors
1 Answer Available

Last Activity: 3 Years ago