Please help: Find the angle between the given vectors to the nearest tenth of a degree. u = , v = 3.0° 6.0° -7.0° 16.0°

Question

Please help: Find the angle between the given vectors to the nearest tenth of a degree. u = <2, -4>, v = <3, -8> 3.0° 6.0° -7.0° 16.0°

amistre64 · Answer

u.v
arccos (  -----------  )
             sqrt(u.u * v.v)

anonymous · Answer

doesnt that make arccos of 1?

anonymous · Answer

since the sqrt will take off the squared? making the top equal to the bottom

amistre64 · Answer

the sqrt doesnt take off the dot products ...

amistre64 · Answer

u = <2, -4> u = <2, -4> ----------- dot: 4 + 16 = 20 v = <3, -8> v = <3, -8> ----------- dot: 9 + 64 = 73 the sqrt(20*73) is not equal to 20*73

amistre64 · Answer

u = <2, -4> v = <3, -8> ------------ dot: 6 + 32 = 40

amistre64 · Answer

well, 6+32 = 38