Answer:
COS 7.51
Explanation:
3i-4j-5k + 6i+2j-5k
now,
= (3i - 4j + 5k).(6i + 2j - 5k)
= (3.6 - 4.6 + 5.-5)
= (18 - 24 - 25)
= -31
Magnitude of A is SQRT 3^2 - 4^2 - 5^2 = SQRT 9 -16-25 = SQ -32
Magnitude of B IS SQRT 6^2+2^2-5^2 = SQRT 36+4-25 = SQRT 15
COS THETA = -31 / SQ RT -32+15 = -31/ SQ RT 17 = -7.51860438
COS THETA = COS 7.51
