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nyc_function answered: 2728 problems
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1 solutions
Answer 223307 by nyc_function(2733)   on 2010-06-08 07:53:13 (Show Source):
You can put this solution on YOUR website!We are looking for percent.
Let p = percent
45 = p times 25
This can be expressed as 45 = 25p.
To find your percent, divide both sides by 25.
45/25 = p
1.8 = p
The answer is 1.8%
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The Proof:
Going back to your original question, if we multiply 25 by 1.8, we'll get 45 proving that 1.8% is correct.
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Age_Word_Problems/312394: Adding two years to the age of a boy would make him a quartet of his father's age. Five years ago his father was one year less than ten times his son's age. Determine the age of the boy and his father
1 solutions
Answer 223306 by nyc_function(2733) on 2010-06-08 07:47:29 (Show Source):
You can put this solution on YOUR website!We have a system of equations in two variables expressed as an age question.
Let: b = boy's age now
Let f = father's age now
first sentence and equation:
b + 2 = f/4, f = 4b + 8 eq.1
2nd sentence and equation:
5 yrs ago, their ages were:
For the boy : b - 5
for the father: f - 5
f - 5 = 10 (b-5) - 1
simplifying
f = 10 b - 46 eq.2
Equate equations 1 and 2
4b + 8 = 10b - 46
b = 9 yrs. old
The boy is 9 years old.
f = 4(9) + 8
f = 44 yrs.old
The father is 44 years old.
Understand?
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Numbers_Word_Problems/312395: what are three consecutive odd numbers that add up to 357?
1 solutions
Answer 223305 by nyc_function(2733) on 2010-06-08 07:45:14 (Show Source):
You can put this solution on YOUR website!Let x = first odd number
Let x + 2 = second odd number
Let x + 4 = third odd number
Here is your equation:
x + x + 2 + x + 4 = 357
3x + 6 = 357
3x = 357 - 6
3x = 351
x = 351/3
x = 117
Here are the three consecutive odd numbers:
x = 117
x + 2 = 117 + 2 = 119
x + 4 = 117 + 4 = 121
They are: 117, 119, 121
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Linear-equations/312396: Write the equation in slope-intercept form of the line that has a slope of -3 and contains the point (1, 1).
1 solutions
Answer 223304 by nyc_function(2733) on 2010-06-08 07:42:03 (Show Source):
You can put this solution on YOUR website!They give you one point and slope. This is all you need to plug into the point-slope formula.
The point-slope formula is: y - a = m(x - b).
If (a,b) represents your point, then a = 1 and b = 1.
If m represents your slope, then m = -3.
We now plug and chug.
y - 1 = -3(x - 1)
y - 1 = -3x + 3
y = -3x + 3 + 1
y = -3x + 4
Done!
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Percentage-and-ratio-word-problems/312218: A transformer has a primary voltage of 480 volts and a secondary voltage of 120 volts. If the primary windings have 700 turns, how many turns are in the secondary windings? (Voltage and number of turns are directly proportional.)
1 solutions
Answer 223224 by nyc_function(2733) on 2010-06-07 18:08:48 (Show Source):
You can put this solution on YOUR website!Let t = number of turns in the secondary windings
480/120 = 700/t
Solve for t and you will have your answer.
HINT: Cross-multiply and then divide to find t.
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Quadratic_Equations/312216: Use the quadratic formula to determine the x-intercepts (if any) of the following function. Then evaluate the function for several values of x, and use the resulting points to graph the function.
f(x) = -x2 + 2x - 2
1 solutions
Answer 223223 by nyc_function(2733) on 2010-06-07 18:05:19 (Show Source):
You can put this solution on YOUR website!Let y = f(x)
To find the x-intercepts, let y = 0 and solve for x.
To evaluate the function, select different value for x, plug them into your function and do the math. You can use any number. I will give you 4 to play with. Let x = -2, -1, 0, 1.
To graph the function, go to mathway.com and in the graph category, write the following: Graph y = -x^2 + 2x - 2.
Is this clear?
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Circles/312210: Determine the center and the radius of the circle x^2+(y+5)^2=17
1 solutions
Answer 223220 by nyc_function(2733) on 2010-06-07 18:00:10 (Show Source):
You can put this solution on YOUR website!The general formula for a circle not center at the origin is
(x - h)^2 + (y - k)^2 = r^2
You were given x^2 +(y+5)^2 = 17.
The center is (h,k). From your equation, I can see that h = 0 and k = -5.
The center is (0,-5).
The radius = r in the general formula for a circle.
r^2 = 17
r = sqrt{17}.
The center is the point (0,-5) and the radius is the square root of 17 written
sqrt{17}.
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Travel_Word_Problems/312201: My friend and I are heading to board a plane. My friend rides on an escalator while I walk along side the escalator. If my friend is travelling at 6 miles per hour while I am walking at 4 miles per hour. How far (approximately) will my friend be ahead of me after 20 minutes?
1 solutions
Answer 223212 by nyc_function(2733) on 2010-06-07 17:41:59 (Show Source):
You can put this solution on YOUR website!Well, if you guys walked for an hour, obviously, your friend would go six miles and you would go four. The difference is two miles. But that's for an hour. For twenty minutes, simply divide the two miles by 3 (20 minutes is one third of an hour), so your friend would be 2/3 miles (3520 feet) ahead of you.
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Trigonometry-basics/312198: Value of angles in degrees for a right triangle whose legs are 0.5' and 4.0'
1 solutions
Answer 223206 by nyc_function(2733) on 2010-06-07 17:18:01 (Show Source):
You can put this solution on YOUR website!Sorry about the first reply. I read your question a second time. Use the Pythagorean Theorem to find the hypotenuse. Then use the sine and cosine trig functions to find the other angles. Can you do it now? If not, write back.
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test/312199: A model rocket is shot into the air and its path is approximated by , where h is the height of the rocket above the ground in metres and t is the elapsed time in seconds.
a. When will the rocket hit the ground?
b. What is the maximum height of the rocket?
1 solutions
Answer 223205 by nyc_function(2733) on 2010-06-07 17:12:54 (Show Source):
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Trigonometry-basics/312171: Please help me with this question and show all steps if possible thank you!
1 solutions
Answer 223186 by nyc_function(2733) on 2010-06-07 16:14:05 (Show Source):
You can put this solution on YOUR website!2sin^2 x - cosx = 0
One of the Pythagorean Identities is sin^2 x = 1 - cos^2 x.
Replace your sin^2 x with 1 - cos^2 x.
2(1 - cos^2 x) - cosx = 0
We now apply the distributive rule from algebra to remove the parentheses.
2 - 2cos^2 x - cosx = 0
Bring everything to the right side of the trig equation and then equate to zero.
0 = 2cos^2 x + cosx - 2
To avoid confusion, replace cosx with any letter of choice to complete the factoring process. Then, at the end, replace the letter your chose with cosx. More about this later.
I will use the letter u but you can use any letter.
2u^2 + u - 2 = 0
Do you recognize that this is a quadratic equation dressed up as a trig function?
We now factor like any other quadratic equation.
To factor, we need to use the quadratic formula from algebra in this case.
After doing the math on paper, I got two answers for u.
Here they are:
u = [-1 + sqrt{17}]/4, which is about 0.781 in decimal form.
AND
u = [-1 - sqrt{17}]/4, which is rejected because the value of cosine must lie between 0 and 1. Do you understand why the negative decimal number must be rejected?
We are working with the positive decimal number. Keep in mind that cosine is positive in the first and fourth quadrants.
We can now replace u with cosx because we are dealing with trigonometry not algebra.
We are working with cosx = 0.781.
Using the inverse cosine key on the calculator, I found the reference angle to be 38 degrees.
Since we are in quadrants 1 and 4, we now find the values of x in those quadrants.
In Quadrant 1:
90 - 38 = 52 degrees
In Quadrant 4:
360 - 38 = 322 degrees
I hope this helps.
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Trigonometry-basics/311280: the lateral surface are of a right circular cone, s, is represented by the equation, S=Pi r^2 radical((r^2+h^2)) , where r is the radius of the circular base and h is the height of the cone. if the lateral surface are of a large funnel is 236.64 square centimeters and its radius is 4.75 centimeters, find its height to the nearest hundredth of a centimeter.
1 solutions
Answer 222621 by nyc_function(2733) on 2010-06-04 10:43:19 (Show Source):
You can put this solution on YOUR website!Replace s with 236.64 and r with 4.75 and then solve for h.
236.64 = pi(4.75)^2 * sqrt{(4.75)^2 + h^2}
I'm sure you can finish now.
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Geometry_proofs/311284: Can u please help me with geometry poofs i have no idea how to do them because im sick and i missed class so can u please help me
thanks
1 solutions
Answer 222620 by nyc_function(2733) on 2010-06-04 10:39:40 (Show Source):
You can put this solution on YOUR website!Copy and paste the following link to learn about geometric proofs.
http://www.regentsprep.org/Regents/math/geometry/math-GEOMETRY.htm
When you enter the provided link, scroll down to Informal and Formal Proof.
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Rectangles/311283: The ratio of the measure of the larger angle to the shorter angle of a golden triangle is the golden ratio?
1 solutions
Answer 222618 by nyc_function(2733) on 2010-06-04 10:34:30 (Show Source):
You can put this solution on YOUR website!Golden triangle?
Perhaps you meant to type golden rectangle.
Do you need to know what the goldern ratio for a golden rectangle is in short?
Golden ratio = length divided by width
Golden ratio = (1 + sqrt{5})/2
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Triangles/311198: Vertices of a triangle A(1,2) B(5,10) C(-7,6)
Show that it is a right triangle.
Find length of each side.
THANK YOU ! (:
1 solutions
Answer 222576 by nyc_function(2733) on 2010-06-04 00:38:42 (Show Source):
You can put this solution on YOUR website!BIG HINT:
Use the distance formula for points written in the form (x,y).
You will use the distance formula to find the distance from A to B, from B to C and from A to C.
To learn about the distance formula, copy and paste the free video clip below.
If you do not understand what to do after watching the math video clip, write back.
http://www.youtube.com/watch?v=YBeXhGl6pSE
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Quadratic_Equations/311225: how do i work out x+11=y and 7x-49=y? (two differwnt equations)
1 solutions
Answer 222573 by nyc_function(2733) on 2010-06-04 00:29:30 (Show Source):
You can put this solution on YOUR website!Solve for x in x + 11 = y.
x + 11 = y
x = y - 11
Now plug that into the other equation to find the value of y.
7x - 49 = y
7(y - 11) - 49 = y
7y - 77 - 49 = y
-126 = -7y + y
-126 = -6y
-126/-6 = y
21 = y
We lastly replace y with 21 in EITHER of the equations given to you to find x.
I will use x + 11 = y but you could use 7x-49 = y if you want to.
x + 11 = y
x + 11 = 21
x = 21 - 11
x = 10
Done!
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Trigonometry-basics/311224: The truck of a leaning tree makes an angle of 12 degrees with the vertical. To prevent the tree from falling over, a 35.0 m rope is attached to the top of the tree and is pegged into level ground some distance away. If the tree is 20.0m from its base to its top, calculate the angle the rope makes with the ground to the nearest degree.
1 solutions
Answer 222571 by nyc_function(2733) on 2010-06-04 00:16:43 (Show Source):
You can put this solution on YOUR website!Di you try drawing this stuff?
Try sinx = 20.0/35
Enter 20.0 into calculator and then divide by 35. After that, press the sine inverse key to find your angle represented here by the letter x.
Can you continue?
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