Help?? anyone? 7th grade math tysm
1 answer:
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x*y' + y = 8x
y' + y/x = 8 .... divide everything by x
dy/dx + y/x = 8
dy/dx + (1/x)*y = 8
We have something in the form
y' + P(x)*y = Q(x)
which is a first order ODE
The integrating factor is
Multiply both sides by the integrating factor (x) and we get the following:
dy/dx + (1/x)*y = 8
x*dy/dx + x*(1/x)*y = x*8
x*dy/dx + y = 8x
y + x*dy/dx = 8x
Note the left hand side is the result of using the product rule on xy. We technically didn't need the integrating factor since we already had the original equation in this format, but I wanted to use it anyway (since other ODE problems may not be as simple).
Since (xy)' turns into y + x*dy/dx, and vice versa, this means
y + x*dy/dx = 8x turns into (xy)' = 8x
Integrating both sides with respect to x leads to
xy = 4x^2 + C
y = (4x^2 + C)/x
y = (4x^2)/x + C/x
y = 4x + Cx^(-1)
where C is a constant. In this case, C = -5 leads to a solution
y = 4x - 5x^(-1)
you can check this answer by deriving both sides with respect to x
dy/dx = 4 + 5x^(-2)
Then plugging this along with y = 4x - 5x^(-1) into the ODE given, and you should find it satisfies that equation.
Answer:
The correct option is (D).
Step-by-step explanation:
It is given that GIKMPR is regular hexagon. It means it has 6 vertices.
Since the central angle is 360 degree. Therefore the central angle between two consecutive vertices is
It is given that the dashed line segments form 30 degree angles.
We have rotated the hexagon about O to map PQ to RF. Since P and R are consecutive vertices, therefore the angle between them is 60 degree.
The vertex R is immediate next to the vertex P in clockwise direction.
So if we rotate the hexagon at 60 degree clockwise about O, then we can maps PQ to RF.
Therefore we can also rotate the hexagon at 300 degree counterclockwise about O, then we can maps PQ to RF.
Therefore option D is correct.
