# Posts by Derek

Total # Posts: 291

**Mason**

solve each of the following equations by the square root method and show your work 4x²-20=0

*September 7, 2008*

**URGENT! Last calculus question!**

Hey! So, I was wondering if someone could answer this. I am mad studying for my exam and I still have a few questions left that I just don't have time to answer, and the assignment is due tomorrow. Thanks and here is the question: Use calculus and algebraic methods to do a...

*July 29, 2008*

**Calculus (final question I promise)**

1. Use calculus and algebraic methods to do a complete analysis (i.e., intercepts, critical points, intervals of increase and decrease, points of inflection, intervals of concavity, local maximum or minimum points) for each of the following functions and then sketch the graph ...

*July 28, 2008*

**Essay**

So, what is your question/problem with this?

*July 25, 2008*

**Urgent CALCULUS**

So, I haven't posted in a while...but now I am stummped! Only question I can't get today! A team of students seeks to make a flag representing their commitment to the earth. They will be using a green triangle inscribed in a yellow semi-circle. Find the maximum area of...

*July 25, 2008*

**Calc.**

What function would have a derivative of ƒ′(x) = 12x2 + 4x − 10? Explain how you arrived at your answer...I believe the answer is this: f(x)=4x^3+2x^2-10x...and I got this using the power rule and multiplying. Thanks.

*July 16, 2008*

**Calc.**

How do I deal with square roots and derivatives? Like: f(x)= Sqrtx....the derivative. find

*July 16, 2008*

**Calc.**

What is the derivative of this: not sure because of the pi.... f(x)=x^pi Thanls.

*July 16, 2008*

**Calculus**

I figured out e but I am confused for the rest of the equation.

*July 15, 2008*

**Calculus**

For the decomposition of Carbon 14, find the age of a prehistoric cave painting discovered in the Lascaux Caves in southern France if the amount of Carbon 14 has decayed to 14.29%...again using calculus formulas. Not sure how to use this equation (content section of course ...

*July 15, 2008*

**Calc.**

Nvm, I figured this out myself. :)

*July 15, 2008*

**Calc.**

My other questions I didn't understand what e was either. My calculator does not allow me to perform the function that you told me. Please further explain.

*July 15, 2008*

**Calc.**

Using calculus: If you invest $5000 compounded continuously at 4% p.a. how much will this investment be worth in 5 years? I am not sure what e is. Should my equation be this: A(t)=Pe^rt A(t)=(5000e^(0.04)(5)) Thanks.

*July 15, 2008*

**Calc.**

yes....f(a+h)-fa)/h

*July 14, 2008*

**Calc.**

For the function ƒ(x) = x^3 - 8x + 3, calculate where a = 5 and h = 2. Simplify before substitution (the simplifying is where I am having problems...not sure if my answer is right). Thanks. Using the limits equation.

*July 14, 2008*

**Calc.**

verify that lim h>0 (e^x+h -e^h)/h=e^x and explain how this illustrates that ƒ′(x) = ln e • ƒ(x) = ƒ(x)... The notes for this section suck big time, so I really don't know where to begin with this. Thanks!

*July 14, 2008*

**Calc.**

Determine the interaction of the line of intersection of the planes x + y - z = 1 and 3x + y + z = 3 with the line of intersection of the planes 2x - y + 2z = 4 and 2x + 2y + z = 1.

*July 10, 2008*

**Calc. for Reiny**

this can be done by projections of two vector. recall that the scalar projection of vector b on vector a is a∙b/│a│ so let's find a point on the give line, e.g. the point B(6,0,1) (I let t=0) draw a perpendicular from your given point P(1,-5,2) to meet ...

*July 10, 2008*

**Calc.-Blanking!**

wait actually I don't think you can do that...but then I have a problem. I am supposed to find the distance of the point to the line or something like that of the point (1,-5,2) and the line r=(6,0,1) + t(3,1,2) but I thought you needed the scalar equation in order to find...

*July 9, 2008*

**Calc.-Blanking!**

Wow, so it is late and I can't think! How do I put this into scalar form: r=(6,0,1) + t(3,1,2)? thanks!

*July 9, 2008*

**Calc.**

Use normal vectors to determine the intersection, if any, for each of the following groups of three planes. Give a geometric interpretation in each case and the number of solutions for the corresponding linear system of equations. If the planes intersect in a line, determine a...

*July 9, 2008*

**Calc.**

Use normal vectors to determine the intersection, if any, for each of the following groups of three planes. Give a geometric interpretation in each case and the number of solutions for the corresponding linear system of equations. If the planes intersect in a line, determine a...

*July 9, 2008*

**Calc.**

I am so confused with this last part of the unit! What in the world is going on: Use normal vectors to determine the interaction, if any, for each of the following pairs of planes. Give a geometric interpretation in each case and the number of solutions for the corresponding ...

*July 9, 2008*

**For Everyone on Jiskha**

Hey, I just wanted to say a HUGE THANKS to everyone on this website for helping me out so far with calculus. I am actually understanding a lot because of the help I am getting, you are all a really big help. I appreciate it so much thanks!

*July 7, 2008*

**Calc.**

I just copied the question as it was...I tried asking a friend and the teacher about k. When I tried to work it out, I assumed that the direction vector was 0, because it was not k+t or any number at all, but I am still unsure. Thanks.

*July 7, 2008*

**Calc.**

Determine the value of k so that the line with parametric equations x = 2 + 3t, y = -2 + 5t, z = k is parallel to the plane with equation 4x + 3y – 3z -12 = 0

*July 7, 2008*

**Calc.**

An air ambulance is travelling from Barrie to Toronto. Toronto is located 90 km [S5°E] of Barrie. If the wind is blowing from the South with a velocity of 62 km/h, and the plane’s air speed is 375 km/h, what direction must the pilot fly to make it to Toronto? How do I...

*July 6, 2008*

**Summer School Calculus**

I don't know how to answer this: A vector can be used to represent the path of a drill tip used to bore a deep mine shaft in Sudbury one quarter of the way to the centre of the Earth. Represent the vector using a directed line segment and Cartesian co-ordinates and ...

*July 5, 2008*

**Calc.**

Determine vector, parametric and, if possible, symmetric equations for the line through Q(2, -1, 3) and the mid-point of the line segment from L(3, -2, 5) to M(1, 4, -7). Not sure what to do with the mid-point.

*July 4, 2008*

**Calculus:Help!**

Ok, well both sides are equal yes, but you can't actually do what they are asking right? Because you do the brackets first, and a dot product provides a scalar answer, therefore, you can't add a scalar to a vector, because that is meaningless. Is this correct?

*July 3, 2008*

**Calculus:Help!**

Verify using an example that a + ( b• c) = (a •b ) +c ? Explain your reasoning. I have been over this a thousand times and I don't understand (the notes I was given online are incorrect so I don't know how to answer this). THANKS!

*July 3, 2008*

**Calculus:Help!**

Any ideas on how to solve this: Use a vector solution to show that a scalar equation for the line through the points P1(x1, y1) and P2(x2, y2) is y-y1/x-x1 = y2-y1/x2-x1? Very confused as to what is meant by this question. Thanks.

*July 3, 2008*

**Calculus**

Yup, I got it, it should be r= (-1,4) + (3,-5), tER..yay for me! lol

*July 3, 2008*

**Calculus**

I think I found my mistake, I added wrong lol!

*July 3, 2008*

**Calculus**

Determine a vector equation for the line through the points (-1, 4) and (2, -1). I said: r= (-1,4) + (4,-5), tER, is that correct?

*July 3, 2008*

**Calculus**

So, yet again, I am confused! State whether or not the following statements are true. Justify your reasoning. a). a• ( b+c ) = a• b + a • c b.) a × ( b+c ) = a × b + a × c c.) a × ( b•c ) = a × b • a × c Thanks, again!

*July 2, 2008*

**Calc.**

THANKS!!! You ROCK!!!

*July 2, 2008*

**Calculus**

Well ok, I am confused as to how to draw the diagram. But firstly, I am not sure if you accounted for this, but if a wind is coming from the South, you drawing it pointing in the North direction, if you are coming from somewhere, it means you are travelling in the opposite ...

*July 2, 2008*

**Calculus**

An air ambulance is travelling from Barrie to Toronto. Toronto is located 90 km [S5°E] of Barrie. If the wind is blowing from the South with a velocity of 62 km/h, and the plane’s air speed is 375 km/h, what direction must the pilot fly to make it to Toronto? What on ...

*July 2, 2008*

**Calculus**

What does this mean? For any vector Vector a find Vector a × Vector a. Explain why (this is cross product stuff). Thanks

*July 1, 2008*

**Calculus**

I don't really understand what you mean, sorry. Can you explain it differently?

*June 30, 2008*

**Calculus**

I am asked this: How can you do the cross product of two-dimensional vectors. Well I would have to guess that you just add a 0 in order to follow the cross product method, but this way there is no third component...is this right?

*June 30, 2008*

**Calculus**

My logic was this, as stated from a text book, which also showed your way: the projection of vector a onto b is found by (magnitude a)(magnitude b)(vector b) all over (magnitude b)2

*June 30, 2008*

**Dot product**

I am sure, because I tried looking at the question again. Because the only thing that would make sense would be if k=2 but there would need to be a negative somewhere. Could be a typo. Thanks!

*June 30, 2008*

**Dot product**

I cant get the correct answer and I can't figure out what I am doing wrong. If a=(2,2k) and b=(4,k) are perpendicular, find k. I have worked it out, and I got -2 but it doesn't work when I check it in the original equation. It should be a.b=0 and then plug in the ...

*June 30, 2008*

**Diagram for already posted question**

A force of magnitude 15 N is the resultant of two forces, one of which has a magnitude of 8 N and acts at an angle of 30° to the resultant. Find the magnitude and direction of the other force..what should my diagram look like? Thanks

*June 30, 2008*

**Urgent SUMMER SCHOOL CALCULUS**

I did it a little differently: Horizontal Components: 9cos 60=4.5 and 2cos30=1.7 and added they are 6.2 which gives the horizontal resultant Vertical: 9sin60=7.8 and 2sin30=1 and added they are 8.8 which is the vertical resultant Then using an equation I found magnitude, and ...

*June 29, 2008*

**Urgent SUMMER SCHOOL CALCULUS**

Add these two vectors: I used component law, and I got an answer, but I am unsure as to how to do the direction at the end. Add: 9m/s [N30E] and 2m/s [N60E] I wound up with 10.8m/s and I found an angle of 55 but I am unsure as to what do with the 55: thanks for the help, I ...

*June 29, 2008*

**writing**

Is that your actual thesis statement? And in addition, do not use personal words (I, me, we, us,) and only refer to things as she, he, it, they, after you have specified what you are discussing (just on a side note). Ok, so your thesis statement should be more like: Shoe ...

*June 29, 2008*

**URGENT SUMMER SCHOOL CALCULUS**

My diagram doesn't work out, I have done it to scale, but I can't figure out how to draw it. I got the same answers as everyone above, I used the cosine and sine law to do mine (I got my answer after I posted :) ). But my diagram looks weird. Any thoughts?

*June 29, 2008*

**URGENT SUMMER SCHOOL CALCULUS**

A force of magnitude 15 N is the resultant of two forces, one of which has a magnitude of 8 N and acts at an angle of 30° to the resultant. Find the magnitude and direction of the other force...how do I begin to solve this!?

*June 29, 2008*

**Summer School Calculus**

I think the answer would be 10.8m/s [N35E]. Am I correct?

*June 29, 2008*

**Summer School Calculus**

Add these two vectors: I used component law, and I got an answer, but I am unsure as to how to do the direction at the end. Add: 9m/s [N30E] and 2m/s [N60E] I wound up with 10.8m/s and I found an angle of 55 but I am unsure as to what do with the 55: thanks for the help, I ...

*June 29, 2008*

**Summer School Calculus**

Another one for you :P, add these two vectors using trigonometry (again)... 9N[S2W] and 11N[N31W]...Again, I am confused about the angles, I am not sure what value I should use for the cosine and sine law. THANKS AGAIN!!

*June 29, 2008*

**Summer School Calculus**

Add the following vectors , 7m/s [N30E] and 2m/s [S17E], using trigonometry. Once you draw these out into diagrams, you use the triangle law yes? How do you find the angles to use in the cosine and sine law? A little confused, thanks for the help.

*June 28, 2008*

**CALCULUS**

I used the sine law to get 15 degrees. I am unsure as to what I now do with this angle. Do I add or subtract it somewhere to find the overall angle I am looking for? Thanks again! I owe you!

*June 28, 2008*

**CALCULUS**

Thanks! I agree about the components but the question said specifically to use cosine and sine law :(. Thanks very much though!

*June 28, 2008*

**math**

Oh, it didn't come out right The question was express (5)(sqrt)(72) in simplest radical form I did: sqrt(72)=sqrt(36)*sqrt(2)=(6)sqrt(2) 6*5=30 (30)sqrt(2)=answer Am I on the right track?

*June 9, 2008*

**math**

express 5ã72 in simplest radical form I did this: ã72=ã36*ã2=6ã2 6*5=30 30ã2 Is this right?

*June 9, 2008*

**math**

if the measures of the angles of a triangle are represented by 2x, 3x-15, and 7x+15, the triangle is 1)isosceles triangle 2)right triangle 3)acute triangle 4)equiangular triangle

*May 30, 2008*

**math**

the formula C=5/9(F-32) is used to convert Fahrenheit temperature,F, to Celsius temperature,C. What temperature in Fahrenheit is equivalent to a temperature of 100 Celsius. I know that in Fahrenheit its 212 degrees, but i used it by using guess and check. i need help with how ...

*May 30, 2008*

**math**

which of the following correlations demonstrates a casual relationship? 1)the distance students live from school, and the time it takes to walk there. 2)the amount of money received for allowance and the number of dvd's purcashed. 3)the number of hours spent studying and ...

*May 30, 2008*

**math**

which expression represent the product of 2 consecutive odd integers where n is an odd integer? 1)n(n+1) 2)n(n+2) 3)n(n+3) 4)2n+1

*May 30, 2008*

**math**

if the measures of the angles of a triangle are represented by 2x, 3x-15, and 7x-15, the triangle is 1)an isosceles triangle 2)a right triangle 3)an acute triangle 4)an equiangular triangle

*May 30, 2008*

**math**

what is the expression (6x^3y^6)^2 equivalent to?

*May 30, 2008*

**math**

the formula for potential energy is p=mgh, where p is potential energy, m is mass, g is gravity, and h is height. what expression can be used to represent g?

*May 30, 2008*

**math**

mario paid $44.25 in taxi fare from the hotel to the airport. the cab charged $2.25 for the first mile plus $3.50 for each additional mile. how many miles was it from the hotel to the airport?

*May 30, 2008*

**math**

Which equation represents the direct variation relationship of the equation x/y=1/2? 1)y=x+1/2 2)y=2x 3)y=3x 4)x=2y

*May 30, 2008*

**math**

the base of an isosceles triangle is 5 and its perimeter is 11. The base of a similar isosceles triangle is 10. What is the perimeter of the larger triangle? ithink the perimeter is 16.

*May 30, 2008*

**math**

Debbie goes to a diner famous for its express lunch menu. The menu has 5 appetizers, 3 soups, 7 entrees, 6 vegetables, and 4 desserts. How many different meals consisting of either an appetizr or a soup, one entree, one vegetable, and one dessert can Debbie order? i think that...

*May 27, 2008*

**math**

Running at a constant speed, Andrea covers 15 miles in 2.5 hrs. At this speed, how many minutes will it take her to run 2 miles? I know that I need to use conversion but i don't know how to convert it.

*May 27, 2008*

**math: probability**

A locker combination has three nonzero digits, and digits cannot be repeated. The first two digits are 1 and 2. What is the probability that the third digit is 3?

*March 27, 2008*

**9th grade Health**

What is the ABCs of healthful living

*March 12, 2008*

**physics**

first part: Pi=Pf Pf=0 (train is not moving) 0= m1v1 + m2v2 v2=m1v1/m2

*February 26, 2008*

**math**

Ted is hosting a dinner party. He has a the choice of serving chicken, pasta, or hamburgers for the main course;carrots, lettuce salad, or pineapple for the side dish; and ice cream or cookies for dessert. How many combinations of one main course, one side dish, and one ...

*February 17, 2008*

**math**

Ted is hosting a dinner party. He has a the choice of serving chicken, pasta, or hamburgers for the main course;carrots, lettuce salad, or pineapple for the side dish; and ice cream or cookies for dessert. How many combinations of one main course, one side dish, and one ...

*February 17, 2008*

**geometry**

What help do you need? Please be specific!!!

*February 16, 2008*

**alg 2**

Write an exponential function whose graph passes through the given points. 1. (0, 3) and (1, 15) 2. (0, -5) and (-3, -135) 3. (0, -0.3) and (5, -9.6)

*February 12, 2008*

**English**

what the diference in meaning between the following pairs of sentences 1.Do you like going to the theatre? 2.Would you like to go to the theatre? 1.The first sentence is a yes o no answer.

*December 21, 2007*

**business**

what is a competitive relationship name explain examples

*November 7, 2007*

**english**

Could you help me with these words? lore, lend, increase, and interrupts. Thanks for the help.

*October 29, 2007*

**english**

How do I know if a syllable is stressed or unstressed?

*October 29, 2007*

**AP Chemistry**

I have the following marathon problem but am unsure where to start: A Sample consisting of 22.7g of nongaseous, unstable compound X is placed inside a metal cylinder with a radius of 8.00cm, and a piston is carefully placed on the surface of the compound so that, for all ...

*October 2, 2007*

**AP Chemistry**

I have the following marathon problem but am unsure where to start: A Sample consisting of 22.7g of nongaseous, unstable compound X is placed inside a metal cylinder with a radius of 8.00cm, and a piston is carefully placed on the surface of the compound so that, for all ...

*October 2, 2007*

**calc/physics**

350 J

*April 23, 2007*

**math function rule input/output**

Input 17 28 47 50 54 63 71 Output 59 48 29 26 22 13 5

*March 21, 2007*

**History**

What happened in FLorida in 1909? http://www.fws.gov/policy/029fw3.html

*March 4, 2007*

**Science**

what are the properties of a solid - this is for 5th grade the state in which a substance has no tendency to flow under moderate stress; resists forces (such as compression) that tend to deform it; and retains a definite size and shape Solids have a definite shape, and a ...

*January 16, 2007*

**Science**

what is a the soild material in a solution called? It is called the solute; however, there are many solutions in which no solid is involved. Thank you for helping

*January 16, 2007*

**math**

The product code used by Pitz Toyz consists of a letter, followed by a digit form 1 to 9, followed by another letter, such as A1A. how many different codes are possible?

*October 17, 2006*

**Biology**

In the DNA helix, a ________ (a bicylic nitrogenous base) is always paired with a __________, (a moncyclic nitrogenous base). This occurs because pairing of two of the same kinds of bases would either cause ____________ in the DNA molecule. a. Pyrimidine, purine, hindrance, ...

*July 20, 2006*