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3 years ago

15

If Brenda has 10 math problems to solve and she can solve one math problem per minute how long will it take her to solve all 10

problems

2 answers:

Nina [5.8K]3 years ago

7 0

Answer:she will take 10 minutes

Step-by-step explanation:

Lostsunrise [7]3 years ago

7 0

Answer:10 minutes

Step-by-step explanation: 10x10

It takes 1 minute to solve each question so 10 questions would mean it took ten minutes.

Let me know if that helps :)

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For the function f(x)=3xsquared- 2x+5 find f(1) f(-2) and f(a)

Oksanka [162]

$f(x)=3x^2-2x+5\\\\
f(1):\ \ Substitude\ 1 \ as\ x\ into\ function:\\
f(1)=3*1^2-2*1+5=3-2+5=\textbf{6}\\\\
f(-2)\ \ Substitude\ x=-2\\
f(-2)=3*(-2)^2-2*(-2)+5=3*4+4+5=12+4+5=\textbf{21}\\\\
f(a)\ \ substitude\ x=a\\
f(a)=\underline{3a^2-2a+5}$

4 0

3 years ago

Let f(x) = 1/x^2 (a) Use the definition of the derivatve to find f'(x). (b) Find the equation of the tangent line at x=2

Verdich [7]

Answer:

(a) $f'(x)=-\frac{2}{x^3}$

(b) $y=-0.25x+0.75$

Step-by-step explanation:

The given function is

$f(x)=\frac{1}{x^2}$ .... (1)

According to the first principle of the derivative,

$f'(x)=lim_{h\rightarrow 0}\frac{f(x+h)-f(x)}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{\frac{1}{(x+h)^2}-\frac{1}{x^2}}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{\frac{x^2-(x+h)^2}{x^2(x+h)^2}}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{x^2-x^2-2xh-h^2}{hx^2(x+h)^2}$

$f'(x)=lim_{h\rightarrow 0}\frac{-2xh-h^2}{hx^2(x+h)^2}$

$f'(x)=lim_{h\rightarrow 0}\frac{-h(2x+h)}{hx^2(x+h)^2}$

Cancel out common factors.

$f'(x)=lim_{h\rightarrow 0}\frac{-(2x+h)}{x^2(x+h)^2}$

By applying limit, we get

$f'(x)=\frac{-(2x+0)}{x^2(x+0)^2}$

$f'(x)=\frac{-2x)}{x^4}$

$f'(x)=\frac{-2)}{x^3}$ .... (2)

Therefore $f'(x)=-\frac{2}{x^3}$ .

(b)

Put x=2, to find the y-coordinate of point of tangency.

$f(x)=\frac{1}{2^2}=\frac{1}{4}=0.25$

The coordinates of point of tangency are (2,0.25).

The slope of tangent at x=2 is

$m=(\frac{dy}{dx})_{x=2}=f'(x)_{x=2}$

Substitute x=2 in equation 2.

$f'(2)=\frac{-2}{(2)^3}=\frac{-2}{8}=\frac{-1}{4}=-0.25$

The slope of the tangent line at x=2 is -0.25.

The slope of tangent is -0.25 and the tangent passes through the point (2,0.25).

Using point slope form the equation of tangent is

$y-y_1=m(x-x_1)$

$y-0.25=-0.25(x-2)$

$y-0.25=-0.25x+0.5$

$y=-0.25x+0.5+0.25$

$y=-0.25x+0.75$

Therefore the equation of the tangent line at x=2 is y=-0.25x+0.75.

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3 years ago

A parabola and it’s directrix are shown on the graph. What are the coordinates of the focus of the parabola?

Svetllana [295]

Answer:

a. (0,2)

Step-by-step explanation:

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2 years ago

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Which expression is equivalent to 3x + 2.5(4x + 2)?

Alex787 [66]

Answer:

I think its B

Step-by-step explanation:

Hope this helps:)

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2 years ago

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Yes, a binary tree can be a maxheap. Consider a binary search tree with two values 3 and 5, where 5 is at the root. The tree is

Alchen [17]

Answer:

3 and 5

Step-by-step explanation:

factor tree is more appropriate.

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3 years ago