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
It’s about -1.5555 I think
Step-by-step explanation:
I'll do the first one as an example.
"What are the coordinates of the point on the directed line segment from K(-5,-4) to L(5,1) that partitions the segment into a ratio of 3 to 2?"
Let's call the point we're trying to find P. Ratio of 3 to 2 means that the distance from K to P divided by the distance from P to L is 3/2.
KP / PL = 3 / 2
Which also means the horizontal distances and vertical distances between the points have a ratio of 3:2.
KxPx / PxLx = 3 / 2
KyPy / PyLy = 3 / 2
First, let's use the x coordinates:
(x − (-5)) / (5 − x) = 3 / 2
(x + 5) / (5 − x) = 3 / 2
2 (x + 5) = 3 (5 − x)
2x + 10 = 15 − 3x
5x = 5
x = 1
And now with the y coordinates:
(y − (-4)) / (1 − y) = 3 / 2
(y + 4) / (1 − y) = 3 / 2
2 (y + 4) = 3 (1 − y)
2y + 8 = 3 − 3y
5y = -5
y = -1
So the point P is at (1,-1).
