Monday

January 16, 2017
Total # Posts: 47,908

**PreCalc**

every 10s the amount drops by 1/2, so m(t) = 5 * 2^(-t/10)

*December 4, 2016*

**PreCalc**

clearly, n(t) = 1500*(12000/1500)^t = 1500*8^t = 1500 e^(2.07944t)

*December 4, 2016*

**Math**

suppose I said 8 = r/4 How would you do that? Multiply by the denominator, right? So, r = Td Now divide by T to get d all alone: d = r/T

*December 4, 2016*

**Math**

We are talking about 7*24+1 = 169 hours. So, the clock loses 84.5 minutes in that time. ...

*December 4, 2016*

**Math**

depends on the coins.

*December 4, 2016*

**Math grade 10**

Just verify that they intersect at (3,3)

*December 4, 2016*

**Maths**

sorry. that's ?x-2?

*December 4, 2016*

**Maths**

y = 0.50 for x <= 2 0.50 + 0.10(x-2) for x > 2 technically, it is a step function, so y = 0.50 + 0.10⌈x-1⌉ for x > 2

*December 4, 2016*

**Math**

Just plug in your numbers. (a) H = 27.5 + 2.24*20 (d) 68 = 24+2.32F (e) as femurs lengthen, men grow more slowly

*December 4, 2016*

**Maths**

If the number is ab, then a = 2b 10a+b - 18 = 10b+a

*December 4, 2016*

**Maths**

a+b+c = 1000 a = b+120 b = c+110 b+120 + b + c = 1000 c+110+120 + c+110 + c = 1000 3c+340 = 1000 3c = 660 ...

*December 4, 2016*

**Calculus**

If the man's shadow has length s, then using similar triangles, when the man is x meters from the building, s/15 = 1.69/(15-x) s = 25.35/(15-x) ds/dt = 25.25/(15-x)^2 dx/dt Now plug in your numbers

*December 4, 2016*

**Calculus**

x^2+y^2 = 225 x dx/dt + y dy/dt = 0 now just plug in your numbers and solve for dy/dt

*December 4, 2016*

**math**

naturally, that would be 0.40 * 20, right?

*December 4, 2016*

**Pre-calculus**

These take some practice, but you soon learn the tricks of thinking... #1 r^2 = 4r cos? r = 4cos? #2 (r^2)^2 = 6(r^2 cos^2? - r^2 sin^2?) r^2 = 6(cos^2? - sin^2?) r^2 = 6cos(2?)

*December 4, 2016*

**Math geometry**

42

*December 4, 2016*

**Pre-Calculus**

This article should make things clear. Your function can be massaged to read r = -2/(1+3sin?) http://colalg.math.csusb.edu/~devel/IT/main/m11_conic/src/s08_polar-conics.html

*December 3, 2016*

**Math, Quadratic Functions**

xy = 108 x+2y = 30 x + 2(108/x) = 30 x^2 - 30x + 216 = 0 (x-12)(x-18) = 0 The yard is 12x9

*December 3, 2016*

**Calculus**

if n is even, r = a cos(n?) is a rosette with 2n leaves. Think about it. cos(n?) goes from 1 to 0 every time n? grows by pi/2. So, in [0,2pi], 6? goes in and out 12 times. You can always verify your work online, as at http://www.wolframalpha.com/input/?i=r%3D5cos(6%CE%B8)

*December 3, 2016*

**algebra**

The focus is (14,0) and the directrix is x=0 SO, you have a parabola opening to the right, with 2p=14, and vertex at (7,0) halfway from directrix to focus: y^2 = 28(x-7) http://www.wolframalpha.com/input/?i=parabola+y%5E2+%3D+28(x-7)

*December 3, 2016*

**precalculus**

your values for a,b,c are correct. However, your final answer is wrong, as you could have verified had you tried to check your answer. y = -1/2 x^2 + x + 6

*December 3, 2016*

**maths(trigonometry)**

You cannot mean 10A = 4/3 When you figure out what you mean, then just draw your triangle, and recall that sin? = y/r cos? = x/r

*December 3, 2016*

**tss**

the diameter is twice the radius: 10

*December 3, 2016*

**Math**

v = ?/4 * 0.5^2 * 100 = 25/4 ? ft^3

*December 3, 2016*

**Math 10**

20C3

*December 3, 2016*

**History**

Which is an impact of World War 1 A: German and Russian monarchies became stronger. B: The united states became the largest creditor nation. C: Europeans used their money to buy American goods. D: France no longer had a demand for British goods. My answer is B

*December 3, 2016*

**Math**

A prime number is a number whose factors are only 1 and itself like 17 is a prime number because it's only factors are 1 and 17. 25 is a composite number because it has other factors besides 1 and itself, 25. The factors of 25 are 1,5,and 25. That's why it's a ...

*December 3, 2016*

**Math**

well, 16/60 = 26.67% so, what % scored less?

*December 3, 2016*

**intermediate algebra**

well, it will double three times, right? So, that's 8 times the original amount...

*December 3, 2016*

**Math**

A man left 3/7 of his money to his wife, 1/2 of the remainder to his brother, and the rest he divided equally among his three children. If each of his children received $400, how much did his wife receive? starting with x, 3/7 went to wife, leaving 4/7 1/2 of that, 2/7, went ...

*December 3, 2016*

**math**

he spent the remainder of the 5 hours. That is, 5 - 2 3/10 = 2 7/10

*December 3, 2016*

**Algebra**

posting it again won't get it any more attention, especially after just 11 minutes! Just wastes your time and ours.

*December 2, 2016*

**Algebra**

8 - 3/4 c = 5 -3/4 c = -3 c = -3 * -4/3 = 4 check: 3/4 * 4 = 3 8-3 = 5

*December 2, 2016*

**Math**

well, these two angles add up to 90 degrees, right? So solve for x, and you can get the angle measures.

*December 2, 2016*

**Math - Calculus @My bad.**

Never mind. I rotated around the line y = -1.

*December 2, 2016*

**Math - Calculus**

The graphs intersect at (-4/3,32/3) and (1,6) We are only interested in x>0, so the volume is using discs v = ?[0,1] ?(R^2-r^2) dx where R=8-2x and r=6x^2 v = ?[0,1] ?((8-2x+1)^2-(6x^2+1)^2) dx = 782?/15 Since we are rotating around the line x = -1, the radius is increased ...

*December 2, 2016*

**Math**

using discs (washers), v = ?[0,3^(1/5)] ?(R^2-r^2) dx where R=3 and r=y=x^5 v = ?[0,3^(1/5)] ?(9-x^10) dx = 90?/11 3^(1/5) using shells, v = ?[0,3)] 2?rh dy where r=y and h=x=y^(1/5) v = ?[0,3)] 2?y^(6/5) dy = 90?/11 3^(1/5) You might have showed your work, right?

*December 2, 2016*

**Pre-Calculus**

tan?/sec? = tan?*cos? = sin? rsin? = 2 y = 2

*December 2, 2016*

**Calculus**

tan? = 4 ? = arctan(4) (C)

*December 2, 2016*

**Calculus**

plug and chug: 2xy = 3 2 rcos? rsin? = 3 so, (C)

*December 2, 2016*

**Pre-Calculus**

r = 4sec? r = 4/cos? rcos? = 4 x = 4

*December 2, 2016*

**Pre-Calculus**

recall that tan? = y/x so, your equation is just y/x = -?3 y = -?3 x

*December 2, 2016*

**Calculus**

your turn to show some work

*December 2, 2016*

**Calculus**

Since the region is rotated around x = -3, you should have ?((3+?(9-y^2))^2-9)

*December 2, 2016*

**Calculus - Integrals**

The curves intersect at (0,0) and (2?2,2?4) using discs, v = ?[0,2?2] ?(R^2-r^2) dx where R=?(4x) and r=x^2/2 v = ?[0,2?2] ?(4x-x^4/4) dx = 24??4/5 using shells, v = ?[0,2?4] 2?rh dy where r=y h=(y^2/4)-?(2y) v = ?[0,2?4] 2?y(?(2y)-(y^2/4)) dy = 24??4/5

*December 2, 2016*

**algebra**

actually, it's h(t) = 200 - 16t^2 so, use 11 for t and evaluate it.

*December 2, 2016*

**Calculus**

let f(x) = 4sinx, g(x) = 2cosx. the graphs cross at u=arctan(1/2), so the area is ?[0,u] (g-f) dx + ?[u,.7?] (f-g) dx

*December 2, 2016*

**math**

Since x>7, you want any number greater than 7. How hard is that? Only one choice fits.

*December 2, 2016*

**Calculus**

what's the trouble? The height of each small rectangle is just the distance between the curves, so a = ?[0,1] (2x^2-x^4) - (x^8) dx

*December 2, 2016*

**algebra**

look at the values for n n #people 0 4 1 4*3 2 (4*3)*3 = 4*3^2 ... n 4*3^n why do you repeat all the math? It's very distracting and annoying.

*December 2, 2016*

**Maths**

x-6 = (50-x)+12

*December 2, 2016*

**Math**

ab/2 = 12 a+b = 16

*December 2, 2016*

**Math**

already did! http://www.jiskha.com/display.cgi?id=1480652609

*December 2, 2016*

**math**

so, how many turns required for 1000m? 1000m * 1turn/2.2137m = ? turn

*December 2, 2016*

**Algebra 1B**

But it is not. Try again. It is A.

*December 2, 2016*

**Algebra 1B**

just solve for x when y=0. be careful, as A and D are almost the same

*December 2, 2016*

**math**

Drop an altitude from B to D on AC. Then triangles ABD and CBD are 30-60-90 right triangles. AD = DC = 3?3 so, AC = 6?3 a+b = 9

*December 2, 2016*

**Math**

well, the room is 4x3 tiles

*December 2, 2016*

**Math**

All are ok except #7 ?? and your answer formatting still sucks.

*December 2, 2016*

**Check them please MAth**

I don't see any of your answers to check. And your text formatting is totally bogus, D00d!

*December 2, 2016*

**maths**

Well 100% = 5/5 so, how many fifths are left?

*December 2, 2016*

**Math**

R*I = I ? is irrational I+I = I (usually) R^3 = R so ok there

*December 2, 2016*

**Algebra**

do you know the golden ratio?

*December 2, 2016*

**algebra 2a solving systems using matrices**

Nope. The matrix has no x in row 1.

*December 2, 2016*

**Math**

cos(180-x) = -cos(x) cos(90-x) = sin(x) so you have (0.5)cos^2(x)sin^2(x) = 0.05 cos^2(x) sin^2(x) = 1/10 sin^2(2x) = 1/40 sin(2x) = ±1/(2?10) ...

*December 1, 2016*

**Pre-calc**

one revolution covers 26? inches. Now let's start the conversion. 70mi/hr * 1hr/60min * 5280ft/mi * 12in/ft * 2?rad/26?in = 5686 rad/min

*December 1, 2016*

**Math**

200*20^2 = 200*400 = 80,000 if the answer is -8000 then there has been some mangling. It seems clear that something is wrong, since ()^2 is always positive.

*December 1, 2016*

**math**

Draw a diagram. The angle ? subtending the visible part of the earth is such that cos(?/2) = 1/3 see what you can do with that.

*December 1, 2016*

**Algebra**

visit here for all the details: http://www.mathportal.org/calculators/polynomials-solvers/synthetic-division-calculator.php

*December 1, 2016*

**Algebra**

try here: http://calc101.com/webMathematica/long-divide.jsp

*December 1, 2016*

**deferential calculus**

where is the wall? at the circumference of the courtyard?

*December 1, 2016*

**math**

standard form is just 9.26

*December 1, 2016*

**math**

9 + .2 + .06 = ...

*December 1, 2016*

**Math**

the quotient of x + 2 is incomplete. You need the quotient of ... and ... since division needs a divisor and a dividend.

*December 1, 2016*

**Math**

the areas are in the ratio 3^3:5^2 = 9:25 = 108:300

*December 1, 2016*

**math**

If it takes x hours, then 1/2 + 1/3 = 1/x

*December 1, 2016*

**math seventh grade**

well 550 = 5.5 * 100 so, it will take 100 minutes.

*December 1, 2016*

**Math**

sure, as long as you provide some work on your part. We don't like homework dumps here.

*December 1, 2016*

**Math**

7*18 + 4*14 + 26

*December 1, 2016*

**math**

3x-14 = 8 I suspect a typo. Is it reasonable for a kid to be almost 3 times as old as his grandfather?

*December 1, 2016*

**Math**

30/2.5 = 12

*December 1, 2016*

**Algebra**

4(6+x) = 6+x

*December 1, 2016*

**Algebra**

To fill the whole tank in x hours, 1/5 - 1/7 = 1/x but you only have to fill 1/3, so adjust accordingly.

*December 1, 2016*

**steve plz help me on my math**

just the reverse. The distributive property states that a(b+c) = ab + ac combining stuff inside the parentheses first does not involve the property.

*December 1, 2016*

**math**

huh. They gave you the formula, as well as the numbers. Just evaluate 1000 e^(-.028*50)

*December 1, 2016*

**algebra 2**

a=10 d=15 S6 = 6/2 (2a+5d)

*December 1, 2016*

**maths**

98*3 + x = 100*4

*December 1, 2016*

**math algebra**

just find t where 70*0.62^t = 10 .62^t = 1/7 t log.62 = log 1/7 t = log(1/7)/log(.62) = 4.07

*December 1, 2016*

**Math adding fractions with distributive property**

same as with any other distributive property problem: with: 6(1/2+2/3+3/4) 6(1/2) + 6(2/3) + 6(3/4) 3 + 4 + 4 1/2 11 1/2 without: 6(1/2+2/3+3/4) 6(6/12 + 8/12 + 9/12) 6(21/12) 21/2 11 1/2

*December 1, 2016*

**math**

If c is the hypotenuse, then a^2 + b^2 = 20 a^2+1=20 a = ?19 If not, then a^2 = b^2+c^2 = 1+20 = 21 a = ?21

*December 1, 2016*

**maths**

google alternating harmonic series = log(2) for many proofs and discussions, on different levels of math skills.

*December 1, 2016*

**Math**

for a square of side s, the diagonal is s?2 So, you have s?2 = 10 ...

*December 1, 2016*

**Are All Right? Math**

all are correct.

*December 1, 2016*

**MATH**

The area is a circle plus a cylinder, which can be thought of as a rectangle which has been rolled up.

*December 1, 2016*

**Health**

Sometimes a patient needs additional care that his or her regular physician cannot provide. In this instance, the physician can make a referral for a patient to see another physician. What are the three types of referrals? (1 point) regular, urgent, fast normal, fast, STAT ...

*December 1, 2016*

**maths plz help**

Whatever you copied and pasted from mangled the special characters. Try spelling out special stuff, such as sqrt() etc.

*December 1, 2016*

**Math integer**

-2(3 + -4 + -8 + 7) -2(-1 + -8 + 7) -2(-9 + 7) -2(-2) 4 -2(3 + -4 + -8 + 7) -2(3) + -2(-4) + -2(-8) + -2(7) -6 + 8 + 16 - 14 4 34 = -2(-17) so I'd be interested in how you got -17 from what's inside the parentheses.

*December 1, 2016*

**algebra 1**

f(m) = 12 - m/25

*December 1, 2016*

**Math**

If the average of the 21 students is x, then 21x + 78 + 93 = 23*75

*December 1, 2016*

**Integral Calculus**

since pi/4 = arctan(1) just plug in x=1 into the power series. That gives the actual series.

*December 1, 2016*