Question

Find the angle of intersection of the plane -5x-2y+4z=2 with the plane 3x+3y+5z=5

Answer 1

find the Normals and use the dot product identity on them

Answer 2

dot product of the normal is -1, what do i do with this?

Answer 3

A dot B = |A|*|B|*.........?

Answer 4

how do i get an angle?

Answer 5

if beta is the angle then\[\cos \beta = n1 \dot n2 /( magnitude of n1) * magnitude of n2)\]

Answer 6

numerator has dot product

Answer 7

is n1 and n2 = <-5,-2,4> and <3,3,5>??

Answer 8

good, you are on right track

Answer 9

yeah i used those and i got theta = 91.3026 degrees but it says that is wrong?

Answer 10

what are values of magnitude of n1 and n2 respectively

Answer 11

magnitude of <-5,-2,4> = sqrt(45)
magnitude of <3,3,5> = sqrt(43)

Answer 12

take the product and what do you have

Answer 13

43.9886349

Answer 14

whats in the numerator

Answer 15

ok i got it correct thanks!!

Answer 16

great