Flag Algebra> the angle between the planes r.(3i-4j+5k)...
question mark

the angle between the planes r.(3i-4j+5k)=0 & r.(2i-j-2k) is

Srijan , 11 Years ago
Grade Upto college level
anser 1 Answers
Latika Leekha

Last Activity: 10 Years ago

The given planes are (3i-4j+5k)=0 & (2i-j-2k) .
Let θ be the angle between two planes, then we have
cos θ = (l1.l2) / |l1| . |l2 |, where l1 and l2 are the two vectors
Here, l1.l2 = 3(2) + (-4)(-1) + (5)(-2)
= 6+4-10
= 0.
Now, |l1 | = √ 32 + 42+ 52 = √ 50
and |l2 | = √ 22 + 12+ 22 = √ 9 = 3.
Hence cos θ = (l1.l2) / |l1| . |l2 |
= 0/ √ 50 .3
= 0.
Now cos θ = 0 which means θ = π/2.
Thanks & Regards
Latika Leekha
askIITians Faculty

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