How many 30° angles does it take to make a full turn?

The quadrilateral ABCD has area of 58 in2 and diagonal AC = 14.5 in. Find the length of diagonal BD if AC ⊥ BD.

azamat

Answer:

(look in the the Step by step)

Step-by-step explanation:

When the diagonals of a quadrilateral are perpendicular, the area of that quadrilateral is half the product of their lengths.

.. A = (1/2)*d₁*d₂

Substituting the given information, this becomes

.. 58 in² = (1/2)*(14.5 in)*d₂

.. 2*58/14.5 in = d₂ = 8 in

The length of diagonal BD is 8 in.

4 0

2 years ago

The equation of a parabola is y=x2+6x+9. Write the equation in vertex form.

nignag [31]

Answer:

Step-by-step explanation:

Vertex form is accomplished by completing the square on the quadratic. Do this by first setting the parabola equal to 0 then moving the constant over to the other side:

$x^2+6x=-9$

Now take half the linear term, square it, and add it to both sides. Our linear term is 6. Half of 6 is 3, and 3 squared is 9:

$x^2+6x+9=-9+9$

The reason we do this is to create a perfect square binomial on the left:

$(x+3)^2=0$ (obviously the 0 results from the addition of 9 and -9). Move the 0 back over to the other side and set the quadratic back equal to y:

$(x+3)^2+0=y$

This gives you a vertex of (-3, 0), which is a minimum value, since the parabola opens upwards.

6 0

2 years ago

The library has DVDs on crime, adventure and science fiction.

kozerog [31]

Answer:

The library has 1,056 crime DVDs.

Step-by-step explanatiion:

Crime : Adventure : Science

11x : 6x : 10x

6x+384=10x

384=4x

x=96

The number of crime DVDs is 11x.

We found that x=96.

So, the number of crime DVDs the library has is equal to 11*96.

11*96=1,056.

Hope this helps!

6 0

2 years ago

Implicit differentiation Please help

Anvisha [2.4K]

Answer:

$y''(-1) =8$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Algebra I

Factoring

Calculus

Implicit Differentiation

The derivative of a constant is equal to 0

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Product Rule: $\frac{d}{dx} [f(x)g(x)]=f'(x)g(x) + g'(x)f(x)$

Chain Rule: $\frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)$

Quotient Rule: $\frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}$

Step-by-step explanation:

Step 1: Define

-xy - 2y = -4

Rate of change of the tangent line at point (-1, 4)

Step 2: Differentiate Pt. 1

Find 1st Derivative

Implicit Differentiation [Product Rule/Basic Power Rule]: $-y - xy' - 2y' = 0$
[Algebra] Isolate y' terms: $-xy' - 2y' = y$
[Algebra] Factor y': $y'(-x - 2) = y$
[Algebra] Isolate y': $y' = \frac{y}{-x-2}$
[Algebra] Rewrite: $y' = \frac{-y}{x+2}$

Step 3: Find y

Define equation: $-xy - 2y = -4$
Factor y: $y(-x - 2) = -4$
Isolate y: $y = \frac{-4}{-x-2}$
Simplify: $y = \frac{4}{x+2}$

Step 4: Rewrite 1st Derivative

[Algebra] Substitute in y: $y' = \frac{-\frac{4}{x+2} }{x+2}$
[Algebra] Simplify: $y' = \frac{-4}{(x+2)^2}$

Step 5: Differentiate Pt. 2

Find 2nd Derivative

Differentiate [Quotient Rule/Basic Power Rule]: $y'' = \frac{0(x+2)^2 - 8 \cdot 2(x + 2) \cdot 1}{[(x + 2)^2]^2}$
[Derivative] Simplify: $y'' = \frac{8}{(x+2)^3}$