# Posts by Don

Total # Posts: 581

**math**

what is different between a decimal and a decimal point?

**math**

.in the decimal fractions0.1 and 0.02 the numeral 1 is ?

**math**

what fraction of 6cm is 15mm .

**math**

express64in3 different ways,using only index notation

**Physics**

An electric immersion heater is rated 5 A when connected to a 120V circuit. What is the resistance of the heater? If it takes 168 KJ to heat 500 ml of water from 20 deg C to boiling, how long does it take to heat the water?

**Physics**

Ahhh so its 120*7.5*50seconds 7.5 being the amps that the drill draws and 50 being the time and 120 being the voltage.

**Physics**

Hi bob, could you explain how you came to that calculation, please. As in where did the 1.5 come from, and the 50 joules(it was 50 seconds) I'm lost, could you help? Thanks

**Physics**

An electric drill operates at a potential difference of 120V and draws a current of 1.5 Amps. If it takes 50 seconds to drill a hole in a piece of steel,calculate the amount of electrical energy used by the drill in that time.

**Computer**

I have open office and can't find the symbols tab.. arghh

**Computer**

Hi Ms. Sue ... how do you make the small 3 by itself after the 10?

**Computer**

On a laptop, how do you get the 10 to the 3rd power? ( make a small 3 after the 10?)

**physics**

a 12 Volt car battery supplies 1.0 x 10^3 C of charge to the starter. How much energy is used to start the car? ( it's not 10 cubed, but 10 to the third power)

**physics 30**

an object is thrown from 1.5m above the ground with a velocity of 15m/s and at an angle of 25deg with the ground. using vectors and motion equations, determine how long the object will remain in the air before returning to the ground. ARGHHHHHH help please..

**Physics**

a 70g bag of potato chips contains 1.6MJ of energy. Working at your maximum power, how long would it take to burn this energy?

**Physics**

If I know the length of all 3 sides in a right angle triangle, how do I get the degrees of the other angles? Which formula do I use again?

**Physics 30**

a 2000kg car traveling east at 24m/sec enters an icy (frictionless) intersection and collides with a 3600kg truck traveling south at 10 m/sec. If they become coupled together in the collision, what is their velocity immediately after impact?

**math**

there are 3 arrays for 4, how many arrays can be drawn for each prime numbers

**math**

there are 122 houses,how many times does the digit 2 appear on the letterboxes?

**maath**

there are 3 arrays for 4.how many arrays can be drawn for each prime numbers

**Physics 30**

If a truck moving at 30km/hr accelerates at 2.5m/s^2 to 50 km/hr, what time (in sec) does it take? a. 2.22s b. 5.56s c. 8 s d. 28.8s

**algebra**

if the red river is 500 miles longer than the blue river. if the sum of their lengths is 5550 miles what is the length of each river

**algebra**

Can someone help me figure this out please? when you solve a system of equations by the substitution method, how do you determine whether the system of equations is inconsistent? thank you anyone

**algebra**

I need help. Can someone help me please. Explain how you can determine from the graph of a system of two linear equations in two variables whether it is an inconsistent system of equations. Thank you

**Physics**

(.50 kg )(35.7m/s^2) = ? kilograms meters per second squared

**calc**

by applying rolle's theorem, check whether it is possible that the function f(x) = x^5 + x -17 has two real roots. your reason is that if f(x) has two real roots then by rolle's theorem, f'(x) must be equal to what at certain value of x between these two roots, but...

**chemistry**

Carbon monoxide gas and hydrogen gas are mixed in a two liter flask. The reaction produces methanol gas as the only product. At equilibrium the Keq is 1.1 x 10-5. The flask initially held 6 grams of hydrogen and the equilibrium concentration of hydrogen is 0.1 M. How many ...

**Discete Math**

Show that there must be at least 90 ways to choose six integers from 1 to 15 so that all choices have the same sum.

**Physics 30**

First A(B-A) then subtract B again from that answer. I see A as (0,3.5) and B as (-4.2,0) I hope that's the right way algebraically.

**Physics 30**

Hi Bob ... the first post is actually the question .. subtract B from A(B-A)

**Physics 30**

Vectors A) 3.5 cm North B) 4.2 cm West Algebraically subtract B from A(B-A) Whaaaa? Please help

**math**

a sales representative earned four times as much in the fourth week of jan than any other week in jan what is the income for the fourth week

**math**

If a tree is 10 feet tall after two years and 25 feet tall after 5 years, find the rate of change of growth of the tree if y is the height in feet and x is the number of years. Be sure to give correct units.

**chemistry**

(100g)(.473J/g°C)(x-62°C) =-(500g)(4.184J/g°C)(x-22°C) Q = mass•specific heat•change in temperature Can someone show me how to solve this so i can teach myself before my test on Monday ..thanks for your time

**Math**

Fred runs a lap every 2 minutes and Mark runs a lap every 2.5 minutes. They start together. How long will it be before they are next to each other again?

**Trig**

(x+3)^2/4^2 + (y-2)^2/5^2 The location of the Foci are at: a.(-3,-1) and (-3,-5) b. (-3,2) and (-3,5) c. (-3,-3) and (-3,7) d. (-3,1) and (-3,-5) I get (-3,2) and (-3,5) Am I correct?

**Trig**

The question is: Set up a 2 column proof to show that each of the equations is an identity. Transform the left side to become the right side. a. (tan + cot)^2 = sec^2 + csc^2 I'm having trouble with this. b. (cos + sin)/cos + (cos - sin)/sin = csc sec I'm having ...

**Trig**

Thanks Damon.

**Trig**

The actual question goes : make the left the same as the right: left side: tan/sec - 1 = right side sin/1-cos

**Trig**

(sin/cos)/ ( 1/cos - 1) = I'm stumped

**Trig**

The question says: Set up a 2 column proof to show that each of the following equations is an identity. Transform the left side to become the right side. (tan + cot)^2 = sec^2 + csc^2

**Trig**

Hi Damon .. apparently they want the right side to stay "as is" and for the left side to transform into exactly what the right side says .... sorry

**Trig**

Proving Identities: 2 columns (tan + cot)^2 = sec^2 + csc^2 I'm having trouble breaking down the left side to = the right side.. Any help please

**Trig**

ARGHHHHH now that really was a brain fart on my part ... Thanks a lot Reiny for the help Don

**Trig**

(x+0)^2 + (y+4)^2 = 17 the center would be (0,4) I can't see it any other way ...arghhhh

**Trig**

I'm not sure what your looking for Reiny. It looks like the center of the circle is still (0,4) what am I doing wrong?

**Trig**

the center of a circle x^2 + y^2 + 8y =1 is a. (0,-2) b. (0,4) c. (0,1) d. (0,-4) I believe the answer is (0,4) Am I correct ?

**Trig**

The center of the circle (x+2)^2 + (y-3)^2 =1 is a. (2,3) b. (-2,3) c. (2,-3) d. (-2,-3) I believe b. is the answer, is that correct?

**Trig**

The radius of: (x+2)^2 + (y-3)^2 =9 is 3 is this correct?

**Trig**

If the center of a circle is at (2,2) with a radius of 4 the equation of the graph would be : a) (x-2)^2 + (y-2)^2 = 16 b) (x+2)^2 + (y+2)^2 = 16 I think it would be b is that correct?

**Trig**

Oops, brain fart ... answer is -4/5 i guess it was a long day ... thanks anyway .. Don

**Trig**

Half Angle Identities cosx = 7/25 greater than 270 deg and less than 360 Determine cos 1/2x a. -7rt2/10 b. 7rt2/5 c.7/25 d.-4/5 I get 7rt2/5 Is this correct??

**Trig**

Half angle identities Find exact values of a) cos 1/2 b) sin 1/2 c) tan 1/2 based on: cos = 1/5 greater than 270 deg less than 360 deg. I get a) - rt 3/5 b) rt24/5 and c) does not work out at all .... Help please.. book says for answers a)-rt15/5 b) rt10/5 c) -rt6/3 How do you...

**Trig**

Found my mistake .... All is good now Thanks for the help earlier Damon Don

**Trig**

If sinx = 1/4 Find the exact value of cos2x I used the formula for double angle identities : cos2x = 1-2sin^2x and got the answer 1/2 The book says the answer is 7/8 How would they get to that conclusion?

**Trig**

The answer is 1/8 Is that correct Damon ?

**Trig**

If tanx = 2/3 tany = 1/2 then tan(x-y) = ?? a.7/4 b.7/6 c.1/8 d.8/6 which answer is correct ??

**Trig**

= sin (a+b) = sin 70 Is that right Damon ?

**Trig**

sin45cos25 + cos45sin25 = ?? a. cos70 b. sin70 c. cos20 d. sin 20 which answer is correct ??

**Trig**

cos45cos25 - sin 45sin25 = ?? a. cos70 b. sin70 c. cos 20 d. sin 20 which answer is correct ?

**Trig**

Use reduction identities to determine if the following statement is true or false: tan (A-B) = tan (B-A) Is this starement True or False ?

**Trig**

Rewrite tan 88 deg in terms of its cofunction How does that end up????

**Trig**

cot (tan + cot) = ?

**Trig**

( sec -1 )(sec +1 ) = ?

**Trig**

sin/tan = ?

**Trig - Thanks Damon and Lindsey**

Thanks a bunch

**Trig**

If sin = 2/3 and is a second quadrant angle, determine the exact value of sec^2 could be a. 5/9 b. root5/3 c. 9/4 d. 9/5 Please help.......

**Trig**

The next two steps in solving this trig identity question are ??? 1/csctheta x costheta x sintheta x sectheta = sinsqtheta arghhh need help please

**Trig**

Prove the equation is an identity : csc3theta - csctheta + cottheta/csctheta = cotsqtheta + costheta wow ... try that one

**Trig**

Prove that the equation is an identity: cot4theta - csc4theta = -cot sq theta - csc sq theta How ??

**Trig - Thanks Damon**

Thanks for the help Damon. Much appreciated. Don

**Trig**

Column 1 Column 2 (sin theta + cos theta)sq 1 + 2sin theta cos theta Question : how do you get column 1 to be the same as column 2?? using the trig identities

**Trig**

Column 1 Column 2 sec theta - cos theta tan theta sin theta Question: how do you get column 1 to be the same as column 2 ?? using the eight fundamental identities

**Math C30**

Eight Fundamental Identities Sec thada - Cos thada- on one side tan thada sin thada- on the other side How do you do this ???

**Trig**

Please disregard last question .... wrote it down wrong .. Thanks

**Trig**

Eight Fundamental Identities Sec thada - Cos thada How do I do this?

**Math C30**

The first step in solving the equation: 4 sinx - sinx = 0 is what?

**Physics**

If a force of 20N stretches a spring 15 cm, by what amount will the spring stretch is if a force of 80 N is applied?

**Math C30**

What's next? Solve: cosx(tanx + sqroot3) - sqroot3/2(tanx-sqroot3) Provide exact answers .. help

**Math C30**

In steps how do you go from: y = 25cos pi/200x + 30 to get the answer 44.695

**trig**

write equations expressing: 19cos(theta-50degrees) as a sum of sine and cosine.

**Math C30 ( trig )**

A roof in the shape of an upside down cosine wave is to be buile to cover an arena. The arena is 24m wide, the height of the roof at either side wall is 5m, and the maximum height of the roof is 9m. A) write a function that gives the height of the roof in terms of your ...

**Math C30 ( trig )**

Solve : cosxtanx + root3cosx - root3/2tanx - 3/2 = 0 Give exact answers and formula for the general solution as well as the specific solutions.. Help

**MATH C30**

A roof in the shape of an upside down cosine wave is to be built to cover an arena. The arena is 24 m wide, the height of the roof at either side wall is 5 m, and the max height of the roof is 9m . write the function that gives the height of the roof in terms of the distance ...

**MATH C30**

How to find the amplitude, period, phase shift, vertical shift, and the equation of the primary function of the function: y = -cot(1/3x - pi/6) how to find where the period begins and ends

**MATH C30**

Solve cosxtanx + sqroot3cosx - sqroot3/2tanx - 3/2 = 0 interval 0 to 2 pi exact answers and formula for the general solution as well as the specific solutions. Sorry Steve, missed it last night.

**math c30**

solve cosxtanx + root3cosx - root3/2tanx - 3/2 = 0 exact value answers and formula for the general solution and specific solutions.

**math c30**

what is the domain and range of the function y= -2cos 1/2 ( x + pi/4 ) -2

**math c30**

Solve cosxtanx + root3cosx - root3/2tanx - 3/2 = 0 exact answers and formula for general solution

**Trig**

Solve 2cosxsinx + sinx = 0 using unit circle.

**Trig**

Solve 2cos sq x = 1 using the unit circle.

**Math C30**

Last Question disregard .. ooops Solving Equations Containing Circular Functions .. Solve 2cos^2x=1

**Math C30**

Solving Equations Containing Circular Functions ... Solve 2cos^2=1

**Math C30**

Equations containing circular functions and unit circle... solve 2cosx sinx + sinx = 0

**Math C30**

using unit circle solve: 2cos sq x =1

**Mathj C30**

Solving Equations Containing Circular Functions : Solve 2cosx sinx + sinx = 0 when x is between 0 and 2pi

**Math C30**

Solving Equations Containing Circular Functions : Solve 2cos sq x =1

**physics**

A 130g ball moving at 0.35m/s in the x-direction is subject to a 0.25N force in the - y-direction for 1.0s. Find the magnitude of the ball's momentum change.

**Physis Home work**

Two 0.85Mtrs -long pendulums hang side by side. The masses of the pendulum bobs are 50g and 70g . The lighter bob is pulled aside until its string is horizontal and is then released from rest. It swings down and collides elastically with the other bob at the bottom of its arc...

**Physis Home work**

Two 0.85Mtrs -long pendulums hang side by side. The masses of the pendulum bobs are 50g and 70g . The lighter bob is pulled aside until its string is horizontal and is then released from rest. It swings down and collides elastically with the other bob at the bottom of its arc...

**math c30**

-pi/4 plus 15pi/4 divided by 2=7pi/4 how is the math done regarding the fractions (dividing and multiplying)