# Posts by mat

Total # Posts: 169

**calculus**

Let y = sinx + ztanx,where z is a function of x. If (dy/dx)= z+ cosx, show that (d^2y/dx^2) =-y. I really have no idea how to do this. Please show me

**Differential equations**

Hang on ive just realized I need to use the equation for the volume of a sphere first right? v=4/3pir^3 to find a value to plug into my previous equation. Am I on the right track?

**Differential equations**

Good morning. Quick question. dr/dt=K/r^2 When the radius is 3cm, the radius is increasing at a rate of 5/36pi. Use this fact to find the constant K. I know that the general form of these growth factors is e^kt but im not sure where the rate and the original radius goes. Is it...

**Geometric Transformation, Unit Circle, Maths**

Good morning, I have this question: the matrix A = 0 6 4 12 i) show that it is invertable. ii)Find the equation of the image f(c) of the unit circle c in the form. ax^2+bxy+cy^2=d iii)Calculate the area enclosed by f(c). --------------------------------- So far I have found ...

**parametrics**

How do I work out the second quadrant parametrisation of 5x^2+16y^2=45. I have x=3 cos t, y=3sqrt5/4 sin t so far. Thanks

**Silmultaneous Equations**

Thanks steve, out of interest ive gotten a negative value for one. Since im looking for the tension in L and R strings. That doesnt seem right in which case ive made a mistake in getting to this point.

**Silmultaneous Equations**

Just my variables, its to find tension in two strings. I made them LH and RH in my drawings. I could have easily put T1 and T2 come to think of it...

**Silmultaneous Equations**

Need a bit of help solving the following equations. sqrt(5/8-(sqrt(5)/8))LH+cos (43pi/180)RH = 0 and 1/4(1+sqrt(5)LH+sin(43pi/180)RH-2g=0 What is the best way to start when trying to combine these equations? Thanks

**Statics**

Sorry its angle and slope not andle and slipe...

**Statics**

I would like to write vector expressions and determine the andle the slipe makes with the horizontal for the following. a 2kg block is on a slope and is about to slip down, the coefficient of static friction is 0.4. so far I have W=2g F=Fi N=Nj and tan-1 0.4 = 21.8 degrees. W=...

**Hyperbolas, comic sections**

Dont worry I figured out my own stupidity! Sorry everyone.

**Maths, multiplicative inverse**

Show that -3 is a multiplicative inverse of 17 modulo 26.

**Physics**

A ballistic pendulum is a device for measuring bullet speeds. One of the simplest versions consists of a block of wood hanging from two long cords. (Two cords are used so that the bottom face of the block remains parallel to the floor as the block swings upward.) A 0.013-kg ...

**Physics**

A 0.45-kg soccer ball is kicked at an angle ? above the ground with initial speed vi. Determine the height of the ball as a function of the horizontal distance d it travels down the field.

**Math**

A professor at a school of Architecture designed an asymmetrical A-frame house pictured below. The included angle between sides AB and CB, which measure 30.96 ft and 17.78 ft, respectively, measures 67 degrees. Find the length of side AC.

**Fermats Little Theorem**

Thanks Steve.

**Fermats Little Theorem**

Good morning, Just working through an example but ive gotten stuck and need some help. So find the least residue of 8^123 Mod 61 So 8^60 = 1 (mod 61) 8^120 = (8^60)^2 = 1^2 = 1 (mod 61) 123 = 2*60+3 So 8^2*60+3 = (8^60)^2 x 8^3 = 1^2 x 8^3 = 1 x 512 = 512 Can anyone please let...

**engineering**

A cast-iron saucepan of mass 1.4kg is filled with 5L of water at 15°C, placed on an electric hotplate, and bought up to boiling point. What is the cost of the energy used if the electricity costs 10 cents per kWh and the hotplate has an efficiency of 70%.

**algebra**

Suppose a population of bacteria in a Petri dish has a doubling time of 6 hours. How long will it take for an initial population of 11000 bacteria to reach 20500? Round your answer to two decimal places.

**Maxima, Stationary Points**

Long shot but does anyone have experience of using Maxima (maths program) for finding stationary points. My user guide offers no help, ive tried to manipulate the following derivative to find the stationary points however its not proving helpful. (9*x^6+28*x^4+51*x^2-88*x-10...

**Calculus, Math word problems.**

A closed box is to be made in the shape of a cubiod, of height h cm and with a square base that has sides of length x cm. Its volume V is required to be 500 cm^3. A) write an expression for the V (volume)in terms of h and x. B)Write an expression for the surface area A in ...

**physics**

a wire has a resistance of 6 ohm it is stretched out to a new length which is three times its original length what is the resistance of the longer wire?assume uniform diameter.resistivity and density are constant

**physics**

find the approximate current density when an electric field of 5v/m is applied to a copper conductor.the conductivity of copper is 59.6*10^6

**physics**

I can just use one of them

**physics**

a copper wire with a diameter of 1.5mm is joined to an aluminium wire which has a diameter of 2.3mm.the wire carries a current of 12A.what is the current density in each wire

**Calculus,Stationary Points,First derivative test**

Good afternoon, I need a bit of help. So ive got my first derivative which is 6x^2-6x-12 and the stationary points ive found are x=-1 and x=2 at which points the value of the derivative is zero. So im attempting to classify the points. From my derivative tests the value of -2 ...

**Chemistry**

a)1 b)1 C)2

**math AG3 (algebra/geometry)**

2K^4 * (3K)^2 becomes 2K^4 * 9K^2 because the parenthesis must be removed before doing your multiplication. So the (3K)^2 goes through (3^2)(k^2) to become 9k^2. From there the constants multiply together and the exponents add together, giving you 18K^6.

**College Algebra**

0.08(X) + 0.06(26000-X) = 1800 Distribute 0.08(X) + 1560 - 0.06(X) = 1800 Re-arrange 0.08(X) - 0.06(X) = 240 Subtract Like-terms 0.02(X) = 240 Divide X = 12000 Confirm Results 12000(0.08) = 960 14000(0.06) = 840 960 + 840 = 1800

**Algebra 2**

(a) 6 combinations of Red/Black and 3 combinations of Red/Red (b) There is a 6/18 chance for a Black Checker being drawn so 1/3. There is a 12/18 chance for a Red Checker being drawn so 2/3. (If you draw a black first then the chance of drawing a red drops to 12/17 because a ...

**math**

42

**Math**

...

**math**

The efficiency e of a gasoline engine as a function of its compression ratio r is given by e =1− r1−γ , where γ is a constant. Find γ for e = 0.55 and r = 7.5.

**math**

Given f (t) = t^3 −3 , find f(a - 1).

**math**

By mass a certain material is 75% sand and another is 30% sand. How many tonnes of each must be mixed in order to have 250 tonnes of material that is 50% sand?

**Chemistry help**

How many electrons are in p orbitals in an atom of oxygen? I answered 8 and 6 but it's wrong. Can anyone pls help.

**Physics**

.221

**Geometry**

Of all the shapes, a sphere has the smallest surface area for a volume. Or put another way it can contain the greatest volume for a fixed surface area.

**Physics**

v=1.67

**science**

how do you covert 0.779 kl to l to ml to hl using the decimal method

**Math 2**

Soooo yea idk where u guys got that from o3o

**Math 2**

8 columns and 19 band members becuz 8*19 is egual to 56+96

**math**

1.A father can do a job in a certain number of hours. His son takes twice as long to do the job. Working together, they can do the job in 6 hours. How many hours does it take the father to do the job alone? A.9 B.18 C.12 D.10 3.David is 5 years older than Paul. In 5 years, ...

**math**

This was on my test and have a few more question that is from my test. 18.The Sum of five unequal natural numbers is 90. The second largest of these five numbers can be at the most? A.19 B.41(41 is the right answer) C.44 D.43 E.42 please show work. 22.In what month does the ...

**math**

Michelle will divide 36 herbal tea bags and 48 mint tea bags among gift boxes. Each gift box will have the same number of herbal tea bags and the same number of mint tea bags. What is the greatest number of gift boxes Michelle can make?

**math**

A school booster club is selling T-shirts. The silk screening company is selling shirts to the boosters for $3 each, plus a one-time fee of $150 to cover supply costs. If the boosters want to make at least $300 in profits and they sell a shirt for $12, how many shirts do they ...

**english essay**

can someone proofread my essay please. Martin Luther king Jr, Mrs Gonsalvez, Mr Bryce what do they have in common? Well their leaders. Leaders are people who are kind and caring, But how did they become leaders?. Well they started off as a good student then good citizen then ...

**Math**

Find the real and imaginary parts of the following complex numbers: (i) 1.5e^jπ/4 (ii) je^1.2 + j^2 e

**math**

Use logarithmic differentiation to find the derivative of the function. y = (cos 2x)x

**cal**

from the ans choices i have, I choose 8x^(3/2)-1/4x^(3/2)

**cal**

Find f"(x) for the function. f(x)= x^2+√x

**cal**

Yes, but how would i show the work.

**cal**

Find the integral. ∫ -10 x sin x^2 dx

**cal**

Sketch the graph and show all local extrema and inflection points. f(x)= 1/x^2-2x-8 I believe the ans is "Relative max: [1,-1/9]" and No inflection points".

**science**

what do angiosperms reproduce with??/

**socialstudies(2Qs)**

A woman has just lost her job at an automobile factory.She decides to move some place warmer to look for work in the thriving tourist industry.She is most likely migrating between which two regions? A.from the southeast to the northeast B.from the northwest to the southwest C....

**socialstudies(5Qs)**

thanks but could you let me know the answers because i don't have a book

**socialstudies(5Qs)**

hi guys could you check my social studies answer thanks.oh and if there wrong could you give me the right answer and some information. ---------------------------------------- 1.The climate throughout most of the united states is__________. A.tropical B.temperature C.rainy(i ...

**math**

1.62 is divible by which of the following numbers? A.1,3,31,62 B.1,2,3,31 C.1,4,16,62 D.1,2,31,62 I PICKED D. ------------------------------- 2.108 is divisible by which of the following sets of numbers? A.1,2,3,4,6,9,12,18,27,36,54,108 b.1,2,4,27,54,108 C.1,2,3,6,18,36,54,108...

**Math**

That's what they call dms and it's just another set of units for angles. To convert you can do the math or you can look up a calculator to convert the seconds and minutes back to a decimal in degrees.

**algebra 1**

Look up the definitions and search for examples of these types of numbers. Here are some examples that might help get you started. real = 2 rational = 1/3 (although it goes .3333, it repeats indicating rationlaity) irrationsl = π (3.1415... no matter how far you go the ...

**Math**

The number is 8.23 You just have to think about it like this if it's rounded to 8.2 either the first two numbers are 8.2 or the 8.1 since it has to round to .2 the numbers before it can be bewteen .0 - .4 to make it stay .2 or .5 -.9. Now at the same time think what can we...

**physics**

What is the apparent weight of a 25kg lead block submerged in the dead sea? (density of dead sea is 1240kg/m3)

**physics (please help elena)**

raiz quadrada de (GM/RS^2)

**Psychology**

A fleet of large trucks arrived in the mall parking lot after Janelle parked her car. When she returned to the lot she could not find her small vehicle in the maze of huge trucks. It took her at least half an hour of searching before she located her car. When telling the story...

**Psychology**

Do you think John forgets the time of his appointments? Perhaps he is always late because it makes him feel powerful or, maybe he is just disorganized?" These questions are being asked in order to
A. determine whether John's tardiness is ...

**Psychology**

Unfortunately I have a D in the class, but I am an A student." When there is a difference between what I believe and what I do,
A. cognitive dissonance will develop.
B. social cognition will be less decisive.
C. central route ...

**Psychology**

well then it should be A right?

**Psychology**

One of the interesting aspects of family therapy is the "system" or roles which are assumed by family members. A good example would be _______________.
A. the father sometimes comes home late
B. the mother has difficulty making decisions...

**Psychology**

I have never been a good problem solver. I am not direct enough to be successful," the client complained. "You do not see yourself as a direct problem solver?" responded the therapist. This conversation is typical of _______________.
A. ...

**english**

Ok, I need help with this one also. Some writers like to brainstorm their ideas on a scrap paper before sitting down to write. Others are less intimidated by a blank computer screen or piece of paper, and prefer to dive headfirst into a project. Many students find it useful to...

**english**

people question whether cheerleading is a sport.

**english**

There's more paragraphs, I think the main idea is Cheerleaders.

**english**

Read the following paragraphs and write a topic sentence that expresses the main idea of each. For example, if it is a sport, then some people wonder why cheerleaders must also be concerned with the neatness and uniformity of their appearance. In addition, since cheerleading ...

**Math**

1/3

**Integrals**

Give a geometric description (including a sketch) of the integral 0∫3 2x − 3x dx .

**calculus**

A particle moves in a straight line under a force such that its displacement s(t), in metres, at time t seconds, is given by s(t) = t3 − 5t2 + 3t +15 Find the time at which the particle is at rest?

**calculus**

Find the area of the region between the parabola 4y = x^2 and the line 3x + 4 y = 4

**calculus**

Find the volume of the solid that is obtained when the region under the curve y = 4 − x^2/6 is revolved around the y -axis between y = 0 and y = 4 .

**calculus**

A manufacturer wishes to produce the most economical packaging for detergent. The containers need to hold 25litres and must be cylindrical in shape. What dimensions will ensure that the least amount of plastic is used to create the containers. (Note: the volume and surface ...

**Calculus**

Find the derivative of the following function f(x)=(x-3/2x+3)^2

**Calculus**

There are no parentheses, that's what is confusing me also. The questions is exactly as written above.

**Calculus**

Find the derivative of the following function: f(x)= 10x-3/5x +6x

**Physics**

Help with Problem 3b please!

**physics**

Hey guys, what about #4: Obtain a symbolic expression for the total elongation of the bar, δ. Anybody?

**Physics**

Two identical positive charges exert a repulsive force of 7.0 10-9 N when separated by a distance of 3.2 10-10 m. Calculate the charge of each. _C

**Physics**

Thanks Sat, but can you write your reasoning behind the answer?

**Quantum Physics**

Problem 5 please?

**Quantum Physics**

Answer for Question 5 please?

**math**

Maria gave a store clerk $10.00 for a purchase that cost $9.19. Part A What is the total amount of change Maria should have received from the clerk? Part B How would Maria receive her change using the least number of coins possible? Part C Show 1 way Maria could receive her ...

**Statistics**

33.6

**Physics**

A 2.3 kg block slides down a 25° inclined plane with constant acceleration. The block starts from rest at the top. At the bottom, its velocity is 0.65 m/s. The incline is 1.6 m long. What is the coefficient of friction?

**ENGLISH URGENT !!!!!!!**

Xbox stuff, PS3 stuff, cool shades, and of course cash.

**Math 208**

N=0.04x-78.34 determine the year in which there were 1.9million inmates

**Physics**

An object in equilibrium has three forces exerted on it. A 30 N force acts at 90° from the x axis and a 48 N force acts at 60°. What are the magnitude and direction of the third force? . N ° (counterclockwise from the +x direction)

**Physics- Help**

Five forces act on an object. (1) 63 N at 90° (2) 40 N at 0° (3) 75 N at 270° (4) 40 N at 180° (5) 50 N at 60° What are the magnitude and direction of a sixth force that would produce equilibrium?

**Physics- Help**

Five forces act on an object. (1) 63 N at 90° (2) 40 N at 0° (3) 75 N at 270° (4) 40 N at 180° (5) 50 N at 60° What are the magnitude and direction of a sixth force that would produce equilibrium?

**Physics- Help**

Five forces act on an object. (1) 63 N at 90° (2) 40 N at 0° (3) 75 N at 270° (4) 40 N at 180° (5) 50 N at 60° What are the magnitude and direction of a sixth force that would produce equilibrium?

**Physics**

After a day of testing race cars, you decide to take your own 1590 kg car onto the test track. While moving down the track at 10.0 m/s, you uniformly accelerate to 26.0 m/s in 10 s. What is the average net force that you have applied to the car during the 10 s interval?

**physics**

A diver runs and dives off the end of a spring board that is 0.9 meters above the surface of the water. As she takes off from the diving board, her velocity is 5.2 m/s directed 36° above horizontal calculate: a) the time she is in the air s b) the distance she lands from ...