Solve 9-x y=7 - ScanMath

Question

Solve the equation

Solve for x

Solve for y

x = \frac{2}{y}

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Testing for symmetry

Testing for symmetry about the origin

Testing for symmetry about the x-axis

Testing for symmetry about the y-axis

Symmetry with respect to the origin

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Rewrite the equation

r = \frac{2 sin ( 2 θ )}{∣ sin ( 2 θ ) ∣} r = - \frac{2 sin ( 2 θ )}{∣ sin ( 2 θ ) ∣}

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Find the first derivative

Find the derivative with respect to x

Find the derivative with respect to y

\frac{d y}{d x} = - \frac{y}{x}

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Find the second derivative

Find the second derivative with respect to x

Find the second derivative with respect to y

\frac{d ^{2} y}{d x ^{2}} = \frac{2 y}{x ^{2}}

Calculate

9 - x y = 7

Take the derivative of both sides

\frac{d}{d x} (9 - x y) = \frac{d}{d x} (7)

Calculate the derivative

More Steps

- y - x \frac{d y}{d x} = \frac{d}{d x} (7)

Calculate the derivative

- y - x \frac{d y}{d x} = 0

Move the expression to the right-hand side and change its sign

- x \frac{d y}{d x} = 0 + y

Add the terms

- x \frac{d y}{d x} = y

Divide both sides

\frac{- x \frac{d y}{d x}}{- x} = \frac{y}{- x}

Divide the numbers

\frac{d y}{d x} = \frac{y}{- x}

Use \frac{- a}{b} = \frac{a}{- b} = - \frac{a}{b} to rewrite the fraction

\frac{d y}{d x} = - \frac{y}{x}

Take the derivative of both sides

\frac{d}{d x} (\frac{d y}{d x}) = \frac{d}{d x} (- \frac{y}{x})

Calculate the derivative

\frac{d ^{2} y}{d x ^{2}} = \frac{d}{d x} (- \frac{y}{x})

Use differentiation rules

\frac{d ^{2} y}{d x ^{2}} = - \frac{\frac{d}{d x} ( y ) \times x - y \times \frac{d}{d x} ( x )}{x ^{2}}

Calculate the derivative

More Steps

\frac{d ^{2} y}{d x ^{2}} = - \frac{\frac{d y}{d x} \times x - y \times \frac{d}{d x} ( x )}{x ^{2}}

Use \frac{d}{d x} x^{n} = n x^{n - 1} to find derivative

\frac{d ^{2} y}{d x ^{2}} = - \frac{\frac{d y}{d x} \times x - y \times 1}{x ^{2}}

Use the commutative property to reorder the terms

\frac{d ^{2} y}{d x ^{2}} = - \frac{x \frac{d y}{d x} - y \times 1}{x ^{2}}

Any expression multiplied by 1 remains the same

\frac{d ^{2} y}{d x ^{2}} = - \frac{x \frac{d y}{d x} - y}{x ^{2}}

Use equation \frac{d y}{d x} = - \frac{y}{x} to substitute

\frac{d ^{2} y}{d x ^{2}} = - \frac{x ( - \frac{y}{x} ) - y}{x ^{2}}

Solution

More Steps

\frac{d ^{2} y}{d x ^{2}} = \frac{2 y}{x ^{2}}

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Conic

\frac{( x ^{'} ) ^{2}}{4} - \frac{( y ^{'} ) ^{2}}{4} = 1

Evaluate

9 - x y = 7

Move the expression to the left side

9 - x y - 7 = 0

Calculate

2 - x y = 0

The coefficients A,B and C of the general equation are A= 0,B= - 1 and C= 0

A = 0 B = - 1 C = 0

To find the angle of rotation θ,substitute the values of A,B and C into the formula cot (2 θ) = \frac{A - C}{B}

cot (2 θ) = \frac{0 - 0}{- 1}

Calculate

cot (2 θ) = 0

Using the unit circle,find the smallest positive angle for which the cotangent is 0

2 θ = \frac{π}{2}

Calculate

θ = \frac{π}{4}

To rotate the axes,use the equation of rotation and substitute \frac{π}{4} for θ

x = x^{'} cos (\frac{π}{4}) - y^{'} sin (\frac{π}{4}) y = x^{'} sin (\frac{π}{4}) + y^{'} cos (\frac{π}{4})

Calculate

x = x^{'} \times \frac{2}{2} - y^{'} sin (\frac{π}{4}) y = x^{'} sin (\frac{π}{4}) + y^{'} cos (\frac{π}{4})

Calculate

x = x^{'} \times \frac{2}{2} - y^{'} \times \frac{2}{2} y = x^{'} sin (\frac{π}{4}) + y^{'} cos (\frac{π}{4})

Calculate

x = x^{'} \times \frac{2}{2} - y^{'} \times \frac{2}{2} y = x^{'} \times \frac{2}{2} + y^{'} cos (\frac{π}{4})

Calculate

x = x^{'} \times \frac{2}{2} - y^{'} \times \frac{2}{2} y = x^{'} \times \frac{2}{2} + y^{'} \times \frac{2}{2}

Substitute x and y into the original equation 2 - x y = 0

2 - (x^{'} \times \frac{2}{2} - y^{'} \times \frac{2}{2}) (x^{'} \times \frac{2}{2} + y^{'} \times \frac{2}{2}) = 0

Calculate

More Steps

2 + \frac{1}{2} (y^{'})^{2} - \frac{1}{2} (x^{'})^{2} = 0

Move the constant to the right-hand side and change its sign

\frac{1}{2} (y^{'})^{2} - \frac{1}{2} (x^{'})^{2} = 0 - 2

Removing 0 doesn't change the value,so remove it from the expression

\frac{1}{2} (y^{'})^{2} - \frac{1}{2} (x^{'})^{2} = - 2

Use the commutative property to reorder the terms

- \frac{1}{2} (x^{'})^{2} + \frac{1}{2} (y^{'})^{2} = - 2

Multiply both sides of the equation by - \frac{1}{2}

(- \frac{1}{2} (x^{'})^{2} + \frac{1}{2} (y^{'})^{2}) (- \frac{1}{2}) = - 2 (- \frac{1}{2})

Multiply the terms

More Steps

\frac{1}{4} (x^{'})^{2} - \frac{1}{4} (y^{'})^{2} = - 2 (- \frac{1}{2})

Multiply the terms

More Steps

\frac{1}{4} (x^{'})^{2} - \frac{1}{4} (y^{'})^{2} = 1

Use a = \frac{1}{\frac{1}{a}} to transform the expression

\frac{( x ^{'} ) ^{2}}{4} - \frac{1}{4} (y^{'})^{2} = 1

Solution

\frac{( x ^{'} ) ^{2}}{4} - \frac{( y ^{'} ) ^{2}}{4} = 1

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