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3 years ago

What is 9 - (-8) = 20 and how did you get that answer?

Mathematics

2 answers:

mash [69]3 years ago

7 0

Answer:

9 -( -8)= 9 + 8= 17 not 20

17 is the solution

Colt1911 [192]3 years ago

4 0

Answer: No solution

Step-by-step explanation:

9-(-8)=20 given

9+8=20 the two negatives cancel out, making the eight positive

17=20 this statement is not correct, so the answer is no solution

no solution

I'm not sure if there was supposed to be a variable in there somewhere, but I did my best to explain. Hope this helps!

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polet [3.4K]

Answer:

30/7

Step-by-step explanation:

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3 years ago

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Step-by-step explanation:

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15. If x=a Sin2t (I+Cos2t) and y=b Cos 2t (1-Cos2t) then find dy/dx at =22/7*4

Sav [38]

By the chain rule,

$\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\mathrm dy}{\mathrm dt}\dfrac{\mathrm dt}{\mathrm dx}\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{\frac{\mathrm dy}{\mathrm dt}}{\frac{\mathrm dx}{\mathrm dt}}$

It looks like we're given

$\begin{cases}x=a\sin(2t)(1+\cos(2t))\\y=b\cos(2t)(1-\cos(2t))\end{cases}$

where a and b are presumably constant.

Recall that

$\cos^2t=\dfrac{1+\cos(2t)}2$

$\sin^2t=\dfrac{1-\cos(2t)}2$

so that

$\begin{cases}x=2a\sin(2t)\cos^2t\\y=2b\cos(2t)\sin^2t\end{cases}$

Then we have

$\dfrac{\mathrm dx}{\mathrm dt}=4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t$

$\dfrac{\mathrm dy}{\mathrm dt}=-4b\sin(2t)\sin^2t+4b\cos(2t)\sin t\cos t$

$\implies\dfrac{\mathrm dy}{\mathrm dx}=\dfrac{4b\cos(2t)\sin t\cos t-4b\sin(2t)\sin^2}{4a\cos(2t)\cos^2t-4a\sin(2t)\cos t\sin t}$

$\implies\boxed{\dfrac{\mathrm dy}{\mathrm dx}=\dfrac ba\tan t}$

where the last reduction follows from dividing through everything by $\cos(2t)\cos^2t$ and simplifying.

I'm not sure at which point you're supposed to evaluate the derivative (22/7*4, as in 88/7? or something else?), so I'll leave that to you.

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3 years ago

Maria walks 2 laps in 5 minutes and then runs 2 laps in 3 minutes. If she continues to alternate walking and running at the same

iragen [17]

Answer:

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Step-by-step explanation:

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2 years ago

In the equation y = 4 x, if the value of x is increased by 2, what is the effect on the value of y ?

oksian1 [2.3K]

$y=4(x+2)\\
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The value of y will increase by 8.

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3 years ago

Read 2 more answers