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SIZIF [17.4K]
3 years ago
6

Mike's Bikes has mountain bikes that usually sell for $275 on sale for $220. Mike used this ratio to find the percent change. Is

he correct? Explain.
Mathematics
2 answers:
MrRa [10]3 years ago
4 0

No. Mike wrote the ratio as the amount of change to the new amount. He should have used the ratio of the amount of change to the original amount, which is 55

55/275 , or 20%.

zhannawk [14.2K]3 years ago
4 0
20%
220 divided by 275 to get .8 
80% then 80% minus 100%
=20%
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Square root of 2tanxcosx-tanx=0
kobusy [5.1K]
If you're using the app, try seeing this answer through your browser:  brainly.com/question/3242555

——————————

Solve the trigonometric equation:

\mathsf{\sqrt{2\,tan\,x\,cos\,x}-tan\,x=0}\\\\ \mathsf{\sqrt{2\cdot \dfrac{sin\,x}{cos\,x}\cdot cos\,x}-tan\,x=0}\\\\\\ \mathsf{\sqrt{2\cdot sin\,x}=tan\,x\qquad\quad(i)}


Restriction for the solution:

\left\{ \begin{array}{l} \mathsf{sin\,x\ge 0}\\\\ \mathsf{tan\,x\ge 0} \end{array} \right.


Square both sides of  (i):

\mathsf{(\sqrt{2\cdot sin\,x})^2=(tan\,x)^2}\\\\ \mathsf{2\cdot sin\,x=tan^2\,x}\\\\ \mathsf{2\cdot sin\,x-tan^2\,x=0}\\\\ \mathsf{\dfrac{2\cdot sin\,x\cdot cos^2\,x}{cos^2\,x}-\dfrac{sin^2\,x}{cos^2\,x}=0}\\\\\\ \mathsf{\dfrac{sin\,x}{cos^2\,x}\cdot \left(2\,cos^2\,x-sin\,x \right )=0\qquad\quad but~~cos^2 x=1-sin^2 x}

\mathsf{\dfrac{sin\,x}{cos^2\,x}\cdot \left[2\cdot (1-sin^2\,x)-sin\,x \right]=0}\\\\\\ \mathsf{\dfrac{sin\,x}{cos^2\,x}\cdot \left[2-2\,sin^2\,x-sin\,x \right]=0}\\\\\\ \mathsf{-\,\dfrac{sin\,x}{cos^2\,x}\cdot \left[2\,sin^2\,x+sin\,x-2 \right]=0}\\\\\\ \mathsf{sin\,x\cdot \left[2\,sin^2\,x+sin\,x-2 \right]=0}


Let

\mathsf{sin\,x=t\qquad (0\le t


So the equation becomes

\mathsf{t\cdot (2t^2+t-2)=0\qquad\quad (ii)}\\\\ \begin{array}{rcl} \mathsf{t=0}&\textsf{ or }&\mathsf{2t^2+t-2=0} \end{array}


Solving the quadratic equation:

\mathsf{2t^2+t-2=0}\quad\longrightarrow\quad\left\{ \begin{array}{l} \mathsf{a=2}\\ \mathsf{b=1}\\ \mathsf{c=-2} \end{array} \right.


\mathsf{\Delta=b^2-4ac}\\\\ \mathsf{\Delta=1^2-4\cdot 2\cdot (-2)}\\\\ \mathsf{\Delta=1+16}\\\\ \mathsf{\Delta=17}


\mathsf{t=\dfrac{-b\pm\sqrt{\Delta}}{2a}}\\\\\\ \mathsf{t=\dfrac{-1\pm\sqrt{17}}{2\cdot 2}}\\\\\\ \mathsf{t=\dfrac{-1\pm\sqrt{17}}{4}}\\\\\\ \begin{array}{rcl} \mathsf{t=\dfrac{-1+\sqrt{17}}{4}}&\textsf{ or }&\mathsf{t=\dfrac{-1-\sqrt{17}}{4}} \end{array}


You can discard the negative value for  t. So the solution for  (ii)  is

\begin{array}{rcl} \mathsf{t=0}&\textsf{ or }&\mathsf{t=\dfrac{\sqrt{17}-1}{4}} \end{array}


Substitute back for  t = sin x.  Remember the restriction for  x:

\begin{array}{rcl} \mathsf{sin\,x=0}&\textsf{ or }&\mathsf{sin\,x=\dfrac{\sqrt{17}-1}{4}}\\\\ \mathsf{x=0+k\cdot 180^\circ}&\textsf{ or }&\mathsf{x=arcsin\bigg(\dfrac{\sqrt{17}-1}{4}\bigg)+k\cdot 360^\circ}\\\\\\ \mathsf{x=k\cdot 180^\circ}&\textsf{ or }&\mathsf{x=51.33^\circ +k\cdot 360^\circ}\quad\longleftarrow\quad\textsf{solution.} \end{array}

where  k  is an integer.


I hope this helps. =)

3 0
3 years ago
What is a correct name for the angle shown?
Masteriza [31]

Answer:

the answer is option B. angle S.

when naming an angle we place the vertex of the angle in the middle. here the angle is RST. But that option is unavailable. very often when there are no other angles interfering with the parent angle, we represent it using one letter that is the mid letter, the vertex. here in this case it is S.

4 0
3 years ago
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Find the variance of the following data. Round your answer to one decimal place. x 1 2 3 4 5 P(X=x) 0.3 0.2 0.2 0.1 0.2
Reptile [31]

The variance of a distribution is the square of the standard deviation

The variance of the data is 2.2

<h3>How to calculate the variance</h3>

Start by calculating the expected value using:

E(x) = \sum x* P(x)

So, we have:

E(x) = 1 * 0.3 + 2* 0.2 +3 * 0.2 + 4 * 0.1 + 5 * 0.2

This gives

E(x) = 2.7

Next, calculate E(x^2) using:

E(x^2) = \sum x^2* P(x)

So, we have:

E(x^2) = 1^2 * 0.3 + 2^2* 0.2 +3^2 * 0.2 + 4^2 * 0.1 + 5^2 * 0.2

E(x^2) = 9.5

The variance is then calculated as:

Var(x) = E(x^2) - (E(x))^2

So, we have:

Var(x) = 9.5 - 2.7^2

Var(x) = 2.21

Approximate

Var(x) = 2.2

Hence, the variance of the data is 2.2

Read more about variance at:

brainly.com/question/15858152

4 0
1 year ago
) Lucy, Soling, Kyan, and Daniel are ordering dinner for their families. Each person spends
melisa1 [442]

Answer:

Lucy is 5(m+3)=65

Soling is 5m-3=65

Kyan is 5m+3=65

Daniel is 5(m-3)=65

Step-by-step explanation:

3 0
3 years ago
How to factor x^2 +3x-4
Vikki [24]
(x +4) * (x -1)
****************************************************


6 0
2 years ago
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