Alternativa A
Justificativa:
u = 4i - 8j
v = 6i + 10j
| u | = raiz(4^2) + (8^2) + (0^2)
| u | = 8,94
| v | = raiz(6^2) + (10^2) + (0^2)
| v | = 11,66
| i j k | i j
| 4 -8 0 | 4 -8
|6 10 0 | 6 10
DP = 0 + 0 + 40k
DS = -48k + 0 + 0
u ^ v = DP - DS
u ^ v = 40k - (-48k)
u ^ v = 88k
| u ^ v | = raiz(88^2)
| u ^ v | = 88
| u ^ v | = | u | | v | senx
senx = | u ^ v | / | u | | v |
senx = 88 / 8,94 . 11,66
x = arcsen 0,844
x = 57,56º
Justificativa:
u = 4i - 8j
v = 6i + 10j
| u | = raiz(4^2) + (8^2) + (0^2)
| u | = 8,94
| v | = raiz(6^2) + (10^2) + (0^2)
| v | = 11,66
| i j k | i j
| 4 -8 0 | 4 -8
|6 10 0 | 6 10
DP = 0 + 0 + 40k
DS = -48k + 0 + 0
u ^ v = DP - DS
u ^ v = 40k - (-48k)
u ^ v = 88k
| u ^ v | = raiz(88^2)
| u ^ v | = 88
| u ^ v | = | u | | v | senx
senx = | u ^ v | / | u | | v |
senx = 88 / 8,94 . 11,66
x = arcsen 0,844
x = 57,56º
