Answer:
i) 28 - 30i
ii) 36 + 28i
Step-by-step explanation:
i) x = 6 + i ⇒2x = 2(6 + i) = 12 + 2i
z = 4 - 8i ⇒ 4z = 4(4 - 8i) = 16 - 32i
2x + 4z = (12 + 2i) + (16 - 32i) = 28 - 30i
ii) w = -1 + 5i and z = 4 - 8i
w × z = (-1 + 5i)(4 - 8i) = -4 + 8i + 20i - 40⇒collect like terms
w × z = -4 + 28i - 40
∵
∴w × z = -4 + 28i - 40(-1) = -4 + 28i + 40 = 36 + 28i
Answer:
(-2, -3)
Step-by-step explanation:
We assume your system of equations is ...
You can subtract the second equation from the first to get
... (2x -y) -(2x -4y) = (-1) -(8)
... 3y = -9 . . . . . collect terms
... y = -3 . . . . . . divide by 3 . . . . this is sufficient to identify the correct answer
Substituting into the first equation, we have ...
... 2x -(-3) = -1
... 2x = -4 . . . . . add -3
... x = -2 . . . . . . .divide by 2
Now, we're sure the answer is (x, y) = (-2, -3).
Answer:
see explanation
Step-by-step explanation:
Using the trigonometric identities
cot A = , tanA =
, cscA =
, secA =
Consider the right side
=
=
= × sinAcosA ( cancel sinAcosA )
= cos²A - sin²A
= cos2A
= left side ⇒ verified
