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2 years ago

Help me plzzz i don't know what to put

Mathematics

1 answer:

Pachacha [2.7K]2 years ago

7 0

The correct answer should be 4. 2 times 0.3 is 0.6. 3.4 plus 0.6 equals 4. ;)

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15 points Math problem

mote1985 [20]

Answer:

increased=150%=0.75

original price =100%

100%*0.75/150

=$0.5

4 0

2 years ago

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.

8 0

3 years ago

A sequence of numbers can be found by using the expression 2n + 7. Find the 3rd

xenn [34]

Answer:

2n+7

=2(3)+7

=6+7

=13

2(3)+7=13

7 0

2 years ago

What is the resulting ordered pair if the value of the independent variable is 5?

eduard

Ｆ（５）　＝　－２　＊　５　＋　１　＝　－９
ｔｈｅ　ｐａｉｒ　ｉｓ　（５，　－９）

6 0

3 years ago

What is the greatest common factor of 42,84,and 105 and how do you find it

klemol [59]

The GCF Of All Those Numbers Would Be 7.
6(7)= 42
12(7)= 84
15(7)= 105

7 0

2 years ago

Help me plzzz i don't know what to put​

Help me plzzz i don't know what to put