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Sphinxa [80]
4 years ago
8

A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 40 cm/s. Find the rate at which th

e area within the circle is increasing after each of the following.
after 1 s = after 3 s = after 7 s =
Mathematics
1 answer:
Sonja [21]4 years ago
5 0
Given : dr/dt = 40 cm/s A = πr^2 dA/dt = 2π r dr/dt case 1: when s = 1, r = 40 dA/dt = 2π(40)(40) = 3200π cm^2/sec case 2: when s = 3, r = 3(4) = 120 cm dA/dt = 2π(120)(40) = 9600π cm^2/sec case 3: ... your turn .....
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Is 83 cm greater than or less than 1 m?
o-na [289]
IT'S OBVIOUSLY LESS THAN 1 M.
1 m = 100 cm
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3 years ago
Solve this equation using the radical equation method
Yuki888 [10]
The domain:
3x+6\geq0\ \ |-6\\3x\geq-6\ \ \ |:3\\x\geq-2\\\\D:x\in\left< -2;\ \infty\right)

2x=\sqrt{3x+6}-1\ \ \ |+1\\\\2x+1=\sqrt{3x+6}\ \ \ \ |^2\\\\(2x+1)^2=\left(\sqrt{3x+6}\right)^2\ \ \ |use:\ (a+b)^2=a^2+2ab+b^2\\\\(2x)^2+2\cdot2x\cdot1+1^2=3x+6\\\\4x^2+4x+1=3x+6\ \ \ \ |-3x-6\\\\4x^2+x-5=0\\\\4x^2-4x+5x-5=0\\\\4x(x-1)+5(x-1)=0\\\\(x-1)(4x+5)=0\iff x-1=0\ \vee\ 4x+5=0\\\\x=1\ \vee\ 4x=-5\\\\x=1\in D\ \vee\ x=-1.25\in D

Answer:\ \boxed{x=-1.25\ \vee\ x=-1}
6 0
3 years ago
Find the surface area of the following figure.
fgiga [73]

Answer:

\boxed{\textsf{\pink{ Hence the TSA of the cuboid is $\sf 32x^2$}}}.

Step-by-step explanation:

A 3D figure is given to us and we need to find the Total Surface area of the 3D figure . So ,

From the cuboid we can see that there are 5 squares in one row on the front face . And there are two rows. So the number of squares on the front face will be 5*2 = 10 .

We know the area of square as ,

\qquad\boxed{\sf Area_{(square)}= side^2}

Hence the area of 10 squares will be 10x² , where x is the side length of each square. Similarly there are 10 squares at the back . Hence their area will be 10x² .

Also there are in total 12 squares sideways 6 on each sides . So their surface area will be 12x² . Hence the total surface area in terms of side of square will be ,

\sf\implies TSA_{(cuboid)}= 10x^2+10x^2+12x^2\\\\\sf\implies\boxed{\sf TSA_{(cuboid)}= 32x^2}

Now let's find out the TSA in terms of side . So here the lenght of the cuboid is equal to the sum of one of the sides of 5 squares .

\sf\implies 5x = l \\\\\sf\implies x = \dfrac{l}{5} \\\\\qquad\qquad\underline\red{ \sf Similarly \ breadth }\\\\\sf\implies b = 3x  \\\\\sf\implies x = \dfrac{ b}{3}

\rule{200}2

Hence the TSA of cuboid in terms of lenght and breadth is :-

\sf\implies TSA_{(cuboid)}= 10x^2+10x^2+12x^2\\\\\sf\implies TSA_{(cuboid)}= 20\bigg(\dfrac{l}{5}\bigg)^2+12\bigg(\dfrac{b}{3}\bigg) \\\\\sf\implies TSA_{(cuboid)}= 20\times\dfrac{l^2}{25}+12\times \dfrac{b^2}{9}\\\\\sf\implies \boxed{\red{\sf TSA_{(cuboid)}= \dfrac{4}{5}l^2 +\dfrac{4}{3}b^2 }}

6 0
3 years ago
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Neporo4naja [7]

Answer:

58/9

Step-by-step explanation:

5/3 +43/9

Lets take the L.C.M first

The L.C.M would be 9

Solve the term by taking 9 as L.C.M

=15+43/9

Add the numerator.

=58/9

The answer is 58/9 ....

7 0
3 years ago
select the value for n that guarantees the equation below has infinitely many solutions. 2 (х + 4) = nx +8
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