Answer:
-6re−r [sin(6θ) - cos(6θ)]
Step-by-step explanation:
the Jacobian is ∂(x, y) /∂(r, θ) = δx/δθ × δy/δr - δx/δr × δy/δθ
x = e−r sin(6θ), y = er cos(6θ)
δx/δθ = -6rcos(6θ)e−r sin(6θ), δx/δr = -sin(6θ)e−r sin(6θ)
δy/δθ = -6rsin(6θ)er cos(6θ), δy/δr = cos(6θ)er cos(6θ)
∂(x, y) /∂(r, θ) = δx/δθ × δy/δr - δx/δr × δy/δθ
= -6rcos(6θ)e−r sin(6θ) × cos(6θ)er cos(6θ) - [-sin(6θ)e−r sin(6θ) × -6rsin(6θ)er cos(6θ)]
= -6rcos²(6θ)e−r (sin(6θ) - cos(6θ)) - 6rsin²(6θ)e−r (sin(6θ) - cos(6θ))
= -6re−r (sin(6θ) - cos(6θ)) [cos²(6θ) + sin²(6θ)]
= -6re−r [sin(6θ) - cos(6θ)] since [cos²(6θ) + sin²(6θ)] = 1
Answer: total profit = $418
======================================================
Work Shown:
June
Income = (4 lawns)*($27 per lawn) = $108
Expenses = ($32 for gas)+($12 for trim line) = $44
Profit = income - expenses = 108-44 = $64
----------------------------
July
Income = (12 lawns)*($20 per lawn) = $240
Expenses = ($89 for gas)+($29 for blade sharpening) = $118
Profit = income - expenses = 240 - 89 = $151
----------------------------
August
Income = (16 lawns)*($20 per lawn) = $320
Expenses = ($101 for gas)+($16 for oil) = $117
Profit = income - expenses = 320-117 = $203
----------------------------
Total profit = (june profit)+(july profit)+(august profit)
Total profit = (64) + (151) + (203)
Total profit = $418
If the final result was negative, then we would call this a loss. However, we have a positive value, so we go with a profit.
Answer:
(-65)/17
Step-by-step explanation:
Evaluate 3/(x - 2) - sqrt(x - 3) where x = 19:
3/(x - 2) - sqrt(x - 3) = 3/(19 - 2) - sqrt(19 - 3)
19 - 3 = 16:
3/(19 - 2) - sqrt(16)
19 - 2 = 17:
3/17 - sqrt(16)
sqrt(16) = sqrt(2^4) = 2^2:
3/17 - 2^2
2^2 = 4:
3/17 - 4
Put 3/17 - 4 over the common denominator 17. 3/17 - 4 = 3/17 + (17 (-4))/17:
3/17 - (4×17)/17
17 (-4) = -68:
3/17 + (-68)/17
3/17 - 68/17 = (3 - 68)/17:
(3 - 68)/17
3 - 68 = -65:
Answer: (-65)/17
