Saturday
April 19, 2014

Posts by Quidditch


Total # Posts: 494

Math
You are doing it correctly. 5(59.4) = 4(61) + x multiply it out... 297 = 244 + x subtract 244 from each side 53 = x

math
First write the problem. 4 < x^(1/2) < 9 Square each term. There are no negative signs, so the inequality signs will not change. Squaring... 16 < x < 81

algebra
Your very welcome!

algebra
Well, let's try your answer: (x-5)(x+5) = x^2 - 25. So, that doesn't work. Doing the factoring I mentioned previously gives: 7x^2(x - 5) - 6(x - 5) Now there are two terms. The terms have a common factor of (x-5). Using our friendly distributive law we can write: (7x^2...

algebra
7x^3 - 35x^2 - 6x + 30 Factor 7x^2 from the first two terms and -6 from the last two terms.

math
For this type of problem, try to get just the variable on one side and just the numbers on the other side. (1/2)a - 5 = (1/3)a - 1 Add 5 to both sides to get rid of the number on the left. (1/2)a - 5 + 5 = (1/3)a - 1 + 5 combining... (1/2)a = (1/3)a + 4 Now subtract (1/3)a fro...

math
The numerator can be factored: (x^4 - 8x^2 + 15) = (x^2 - 3)(x^2 - 5) Use that and cancel the common (x^2 - 3) in the numerator and denominator.

math
1. The solution is an inequality. Also when you multiply or divide by a negative number, the inequality is reversed. from you step: -3x/-3 < 6/-3 Since you are dividing both sides by a negative number the inequality is flipped: x > -2 2. OK

math
4x3x2 are common in both the numerator and denominator. Canceling those leaves just 5 in the numerator.

math
Turn the factorial expressions into product series, cross out common factors in the numerator and denominator.

math
The distance is the hypotenuse of a right triangle where one leg is the x distance and the other leg is the y distance. In this case, the y values are the same so the distance between the points is simply the x distance.

Physics Check
A more complete explanation... The car is traveling horizontally at a constant speed. When it drives off the cliff, it keeps going at the same speed (disregarding friction) until it is stopped by hitting the ground. A forumla for (d) distance traveled with constant acceleratio...

Physics Check
#1 correct #2 correct #3 wrong #4 correct #5 wrong ---- #6 find t in seconds: 122.5m = (0.5)(g)(t^2) 122.5m = (0.5)(9.8m/s^2)t^2 reducing... 25s^2 = t^2 t = +5 seconds and t = -5 seconds Disregard the negative time. That is how long it took to fall 122.5m. So, if the car trave...

Math (Algebra)
Be careful. You posted (72)/(-68) reduces to (-18)/(-17). You had a sign change in the numerator. Probably just a typo, but you might want to check.

math
The slope is 2.

Calculus/Physics
In the equation s(t) = (s0) + (v0)t + (1/2)(a)(t^2) s(t) gives the height for some time t. s0 is the initial height, which is the height of the cliff. v0 is the initial velocity, for this problem 20m/s. The last term is the distance due to gravity. As t^2 increases, this term ...

Calculus/Physics
You have the right formula. Let S0 be the height of the cliff in meters. When the stone stops it is at 0m height. So, 0m = S0 + (v0)t + (1/2)gt^2 t =7 s g=-9.8m/(s^2) 0 = S0 + (20m/s)(7s) + (1/2)(-9.8m/(s^2))(49s^2) 0 = S0 + 140m - 240.1m S0 = 100.1m

Algebra
You have an error in your first step when you multiplied: -2(5 + 4a) It is not -10 + 8a .

Math
Do you see a numeric factor that is common in each term? Factor that number from each term. What is left?

college
v1 = velocity one second later vi = initial velocity of rock = 4.9 m/s t = time in seconds g = acceleration due to gravity = -9.8 m/s^2 v1 = vi + gt Plug the numbers in and solve for v1.

Math
Check how much each number differs from the previous one. Is there any pattern?

algebra
This is similar to your 7:58pm post. In that case we interpreted x^2y as x^(2y) rather than (x^2)y. In that case y was 1, and the value was the same. In this case, I don't see any answers if x is raised to the 2y power. If it is interpreted as 5(x^2)y for the numerator and...

alegbra
putting a few parenthesis in for clarification... 2x^(2y)/(4xy) does = 1 for x=2 and y=1 So, you are correct!

alg
I think that the 4 is probably inside the "crook" of the radical sign to indicate the fourth root of (81/16).

alg
I got a, also.

algebra
If the problem is asking for the fourth root of 625, then c is correct. That would be the case if the 4 is in the crook of the radical sign.

algebra
a is NOT correct.

algebra
Glad to help.

algebra
Yes, I got b, also.

algebra
Your welcome.

algebra
Yes, it is correct.

college physics
Yes, thanks!

college physics
OK, the ramp makes a 40 degree angle with the horizontal. A sketch might help visualizing this. If you move 15m down the ramp what is the change in the y direction (the height)? It is 15m * sin(40degrees). So, the potential energy change is: =(80kg) * 9.8m/sec^2 * (- 15m * sin...

college physics
gravitational potential energy = mgh where: m = mass g = gravitational acceleration h = height So, the change in gravitational potential energy is: delta p = 80kg * 9.8m/sec^2 * (h1 - h2)m

Calculus
This same question was answered Wednesday for your 10:58pm post. Check back a few pages to see it.

Calculus
It probably helps to sketch the ships. The distance between the ships is a right triangle with one leg (the east/west leg) being a constant 50km and the other leg being the TOTAL distance traveled by both ships. Express the distance as a function of time then take the derivati...

math
secant of an angle = hypotenuse/adjacent cosine of an angle = adjacent/hypotenuse What happens when you multiply (hypotenuse/adjacent) x (adjacent/hypotenuse) ?

Math115
1. 5x - 15y = 2 2. 5x - 15y = 3 Subtract equation 2 from equation 1. or 0 = -1 So, you are correct, there is no solution.

Physics
1. Work is the dot product of force and distance. What force is neede to lift the box? 2. The force of gravity here is F= (mass of the ball) times (acceleration of gravity). The work is that force through 2.5 meters.

Trig.
Left off the trailing parenthesis... Area of sector of a circle with radius r for sector given in degrees (theta): A = (1/2)(r^2)(theta)((pi)/(180))

Trig.
Area of sector of a circle with radius r for sector given in degrees (theta): A = (1/2)(r^2)(theta)((pi)/(180)

PSAT - Math
Mike's time equals Paul's time. Let D = Paul's distance in miles Mikes time = (D+4miles)/(7mph) Paul's time = D/5mph (D+4miles)/(7mph) = D/(5mph) Ssolve for D, then find D + 4.

Algebra 1
Yes, you are right!

MATHHH
log2(8)=3 log9(3)=0.5 So, (3)^x = (0.5)^(x+1) ln of both sides (x)(ln(3) = (x+1)(ln(0.5) (ln(3) - ln(0.5))(x)= ln(0.5) calculate ln(3) and ln(0.5) solve for x

algebra
Let N be the number. Remember that 1 percent of a number is 0.01 times the number. 25 percent of a number is 0.25 times that number. So.. (0.25)(N) = 20 Divide both sides by 0.25 to find N.

algebra
X + y = 56 y = 3x Substituting that into the first equation... x + 3x = 56 combining... 4x = 56 Divide both sides by 4 to find the value for x. Once you have the value for x, use the second equation of y = 3x to find the value for y.

algebra
a. is correct b. is not correct You have the right idea. y = 3x. Now substitute 3x in for y in the equation and solve it.

4th grade
What happens when the sound waves hit the hard walls?

Math
let D = diameter Radius is half the diameter. So, r = (1/2) D Substitute that in the given equation and then you will have an equation using the diameter.

Maths
No. How many oranges can you get for 3 peaches? If oranges are half the price of peaches, then 3 peaches are worth 6 oranges. 3 bananas cost the same as 2 oranges, So, you can trade 2 oranges for 3 bananas. How many times can you trade 2 oranges for 3 bananas if you start with...

5th grade-math
Let d = the number of dimes. Let q = the number of quarters. What is known... d * $0.10 + q * $0.25 = $1.95 and... q = d - 2 Substitute the above equation for q into the first equation. That gives an equation only in d. Solve for d. Then plug that value into the second equatio...

math
In the explanation, the angle x and the x length are different items.

math
a) let x = the x length let y = the y length let r = the length from the origin to the x,y point. r^2 = x2 + y^2 sine of x = y/r so y and r are given in the problem. solve for x. cosine of x = x/r

college
For the pseudocode you need to know if variables passed to the module are passed by reference or passed by value. It is likely that they are passed by value. Look at all your display statements. Think what each will show. The "Display" function probably adds end of l...

Math
First calculate the volume of the carton. Then calculate the volume of the tank on the truck. Be careful. The dimensions of the tank on the truck are in feet while the dimensions of the cartons are in inches.

math
You're very welcome.

math
a_n = 21 + (n-1)*(-8) Expand that using the distributive law. The first term, 21, is not multiplied by -8. Only the terms in parenthesis are multiplied by -8.

math
You are close. You have an error: Your step: a_n = 21 + (n - 1) - 8 should be: a_n = 21 + (n - 1) * (-8)

Math
7.53 x 10^3 =7.53 x 1000 = ?

physics
One method to solve this is conservation of energy. initial kinetic energy = final potential energy let m = mass of stone let g = acceleration of gravity let v = initial velocity let h = maximum height (1/2)mv^2 = mgh So, v^2 = 2gh h = (v^2)/g

Physics but algebra problem
Go back and look at the two acceleration equations posted above. Don't forget to include gravity. for 89N: a = (89N - mg)/m m and g are known for 99N; a = (99 -mg)/m The acceleration at 99N should be twice the 89N a.

Physics but algebra problem
My mistake! stupied = stupid See, we all make errors.

Physics but algebra problem
No problem. That is why we are here. You are not being difficult or stupied at all. No one is born knowing this stuff. Some more hints: 2(89N - mg)/m = (99N -mg)/m Let's get rid of the denominator. Multiply both sides by m to get: 2(89N - mg) = (99N - mg) Multiplying out t...

Physics but algebra problem
Mia's post accidently went here. Ignore it.

Physics but algebra problem
Let a = the acceleration for 89N Let m = the bowling balls mass. Let g = acceleration of gravity. So, 2a is the acceleration for 99N. Set up the equation that shows the 99N acceleration is 2 times the 89N acceleration: 2(89N - mg)/m = (99N - mg)/m Solve for m.

Physics but algebra problem
Remember that the acceleration of the bowling ball is the NET force of your lifting and gravity. So, the acceleration of your 89N lifting is: a = (89N - mg)/m where g is gravity. Likewise for the 99N lift: a = (99N - mg)/m

Physics but algebra problem
It doesn't look like there is a solution. First equation: 89N = ma Second equation: 99N = m2a For the second equation, if you divide both sides by 2 you get: 99N/2 = m2a/2 49.5N = ma The first equation says ma = 89N. The second equation says ma = 49.5N Assuming a is consta...

math
Expand all the terms by multiplying them out: 8(2x-3) = -16 16x - 24 = -16 Put all the variable terms on one side and the "just numbers" terms on the other side. 16x = -16 + 24 Now, solve for x.

Geometry
No, the problem requests to the nearest tenth which would be: 13.2 ft. Also, don't forget the units.

Geometry
Your welcome! Glad to help.

Geometry
This is a little tricky. Let R = the radius Let Pi = 3.14 as stated. The circumference is (Pi)(2)(R) The problem already calculates (2)(R) for you as 4.2 ft. So, circumference = (Pi)(4.2) or =(3.14)(4.2) ft. Multiply and round as requested by the problem.

math 115
No. |-2| = 2 So, |10| + |-2| =|10| + 2 = ?

algebra
Let a side have ratio value 5. Let b side have ratio value 12. Let c side have ratio value 13. add the ratios of the sides: 5 + 12 + 13 = T It is given that the perimeter (all sides added) is 15 inches. The length of each side has the same relationship to its ratio as the peri...

geometry
Answered below for the jj post.

math
For a proper fraction, the absolute value of the numerator is less than the absolute value of the denominator. So, 1/3 is a proper fraction 2/3 is a proper fraction Is (2/3)/(1/3) a proper fraction?

pre- algebra
Check your answer... If x = 5 3(5) = (96-75) 15 = 21 So, 5 is not a correct answer.

math am i correct
Yes, you are correct.

trig
assuming that 2cos^2x means 2(cos(x))^2 substitute using (cos(x))^2 = 1 - (sin(x))^2 2(1 - (sin(x))^2) + 3sin(x) = 3 2 - 2(sin(x))^2 + 3sin(x) = 3 for clarity, let u = sin(x) 2 - 2u^2 + 3u = 3 rearranging... 2u^2 - 3 u + 1 = 0 Solve this quadratic to find the values of sin x t...

math
x + 2/x + 3 = x - 1/x + 1 It's usually helpful to get rid of denominators, so multiply both sides by x x^2 + 2 + 3x = x^2 - 1 + x subtract x^2 from both sides 2 + 3x = -1 + x collect like terms 2x = -3 So, x = ?

Math
No, -|-8| - |-11-8| = -8 - |-19| = -8 - 19 = -27

math
The distance is the hypotenuse of the right triangle with a vertical leg distance of 4.6 - 0.6 = 4.0 and a horizontal leg distance of (-4.5) - (-6.2) = 1.7 The hypotenuse = ( (4.0)^2 + (1.7)^2 )^0.5 = (16.0 + 2.89)^0.5 = 4.35

Algebra
For a: root(-21) = root( (21)*(-1) ) = root(21) * root(-1) = root(21) * i That should get you started

Algebra
for g(x) = x-7 only allowing real numbers... Yes, C is the answer.

Maths
(a-b)^2(a+b)+ab(a+b) multiply and combine like terms: First multiply--shown in two steps... =(a^2 - 2ab + b^2)(a + b) + (a^2)b + a(b^2) =a^3 - 2(a^2)b + a(b^2) + (a^2)b - 2a(b^2) + b^3 + (a^2)b + a(b^2) Now combine terms.

math
Looks good!

Math
Let x = Adam's points Imram's ponts = x - 3 Shakeel's points = 2(Imram's points) or 2(x-3) totaling x + (x - 3) + 2(x-3) = 39

Math
Check your work. When you multiplied (2x) times (3x) you got 6x. It should be 6x^2

math (am i correct)
1 is not 46.9. Question 1 asks you to find a linear function that fits the data. Find a function f(t) where t is the number of years since 1920. There are two points given. 1920, 46.9s 1990, 45.5s Or, for t expressed as years since 1920... 0 years, 46.9s 70 years, 45.5s for a ...

Math-Linear Systems
A quick check of your answer for b shows a problem. The second equation is: 2x + 5y = 10 Substituting the answer (10,2)... 2(10) + 5(2) = 10 or 20 + 10 = 10 Not correct

Math-Linear Systems
Checking (a) only, (1, 0) is not correct. To check your answer, substitute the values into either equation. So, y = 4x + 6 substituting your (1,0) answer... 0 = 4(1) + 6 or 0 = 10 which is not equal

Math-Linear Systems
for (a), one method: y = 4x + 6 y = -x + 1 For the standard equation, y = mx + b, m is the slope. If m is the same for both equations, the lines are the same or parallel. If parallel, the will not intersect. This is not the case here. The lines do intersect. There are two equa...

Calculus
For the standard line equation, y=mx+b m is the slope of the line b is the y intercept (where x=0) Take the derivative of the equation. Use that to find the slope of the tangent at (0,8). Once you have the slope and one point (0,8) you can solve for the b.

trig
Given: sin(x+y)=sin(x)cos(y) + cos(x)sin(y) For the case y=x: sin(x+x) = sin(x)cos(x) + cos(x)sin(x) =sin(2x) = 2sin(x)cos(x) or, just to make it easier 2sin(x)cos(x) = sin(2x) so, what does 4sin(x)cos(x) = ?

11th grade Algebra 2/ Trig
recall that log x^y = y log x rewriting... (x+2)(log 10) - (x)(log 10) =(2)(log 10) IF the base is 10 then log 10 = 1. In that case the above reduces to: =2

math
Slope = rise/run Let x = run in feet 1/10 = (5 1/2 feet)/x multiply both sides by x x(1/10) = 5 1/2 feet multiply both sides by 10 x = (10) (5 1/2 feet) You do the last step.

Physics.
Yes, you're right! I missed the last part that stated "through the 20.0 resistor". Sorry about that

Physics.
That's not what I got. The equivalent resistance of the 20 ohm and 15 ohm resistors in parallel is, in ohms, (20 * 15)/(20 + 15). Add that to the 5 ohm resistor connected in series. Finally divide the applied voltage, 100 volts, by the total resistance to get the current.

one more elgebra problem...
The standard equation for a line is: y = mx + b where m = the slope of the line b = the y intercept putting y - 3x = 6 in standard form: y = 3x + 6 Therefore the slope of the line is 3. For lines to be parallel, the slope must be the same. Which of the possible answers has the...

Math
Check rounding--I got slightly different values that rounded to different numbers. Given: C = 90 degrees A = 32 degrees AB = 42 units Therefore, B = 180 - 90- 32 = 58 degrees Sine rule: BC/sin(A) = AC/sin(B) = AB/sin(C) BC/sin(32) = AC/sin(58) = 42/sin(90) BC/(0.5299) = AC/(0....

visual basic
gradeCounter is defined as Integer. Try: If(gradeCounter = 0)...

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