oobleck
Popular questions and responses by oobleck
Calculus  Integration
I ran across this one the other day. See what you can make of it. Find the integral of ecosxsinx  (sinx+cosx)esinx+cosx  esin2x2esinx+1
asked on May 22, 2019

math
(9.719.8)/9.8 = 0.00918 * 100% = 0.918%
posted on June 2, 2020 
Physics
consider the height of the ball. y = v sinθ t  16.1t^2 what is v? no idea, but we do know that with a constant horizontal speed of v cosθ, it flew 196 feet. so, t = 196/(v cosθ) Plug that in, and you just have to solve y = 196 tan30.3°  16.1t^2 =
posted on June 2, 2020 
Chemistry
PV/T is constant, so you want 4.81V/(91.60+273.15) = 1*(21.5*22.4)/273.15
posted on June 2, 2020 
precal
it is discontinuous, because the denominator is zero at x = 2, 5
posted on June 2, 2020 
Calculus
Just treat y as a constant. Then apply the quotient rule
posted on June 2, 2020 
mathemathics
kinda missing some information, eh? If you know how to find the volume and area of a prism, though, it should not be too hard.
posted on June 2, 2020 
MATH
well, 18 is the minimum 42 is the maximum the sum of six odd numbers must be even So only 26 is left.
posted on June 2, 2020 
math
nope. 2 for Jeff 3 for Maria so, Jeff got 2/5 of the shells, not 2/3. This illustrates the difference between probability (2/5) and odds (2:3)
posted on June 2, 2020 
math
one which is just a multiple of another 2/3 = 4/6 = 10/15 etc. They are all equivalent.
posted on June 2, 2020 
Mathematics
the midpoiint of the diameter (2,3) is the center of the circle. So the equation is (x2)^2 + (y3)^2 = r^2 r is half the length of the diameter, so ...
posted on June 2, 2020 
history
whining won't get you help any faster. While you're waiting, have you done some googling?
posted on June 2, 2020 
Chemistry
10 days * 2doses/day * 10mL/dose * 50mg/mL = 10*10*2*50 mg
posted on June 2, 2020 
mathematics
#1 see your previous post #2: sin(cos^1(1x)) Let cosA = 1x Draw a triangle with angle A such that the adjacent leg is (1x) and the hypotenuse is 1. Then the opposite leg is √(1  (1x)^2) = √(2xx^2) Now you can tell sinA. #3. Use the law of sines.
posted on June 2, 2020 
Mathematics
r/b = 2/3, so r = 2/3 b (r3)/b = 3/5 5(r3) = 3b 5(2/3 b  3) = 3b now finish solving for b
posted on June 2, 2020 
mathematics
sqrt(63x)2=0 sqrt(63x) = 2 63x = 4 so, what do you think?
posted on June 2, 2020 
Mathematics
hav B = 0.2351
posted on June 2, 2020 
Mathematics
= t(8t)
posted on June 1, 2020 
math
75% and 25% are multiples of 1/4 So how many multiples of 4 are there in 1000?
posted on June 1, 2020 
math
.75 * 100 = 75
posted on June 1, 2020 
Mathematics
You have two pairs of triangles, right? You have the base and height, so just do the math.
posted on June 1, 2020 
Math
well, it is clear that you keep multiplying by 4, right? That only leaves one choice
posted on June 1, 2020 
Precalculus
y = (t3)^2  4 = t^26t+5
posted on June 1, 2020 
Physics
did it burst into flame?
posted on June 1, 2020 
maths
since f(x) is defined for x=2, it is just 2^2+1 = 5 for x>2, the limit would be (23)^2 = 1 Since the limits are not the same, you cannot have both f(x)={x²+1 if x≤2 {(x3)² if x≥2 it must be either f(x)={x²+1 if x≤2 {(x3)² if x>2 or f(x)={x²+1
posted on June 1, 2020 
mathematics
you want 0.095 to be 9.5x10^___ how many places to the right did you shift the decimal point?
posted on June 1, 2020 
Maths
(2W)(2L) = 4WL 4 times the area, 4 times the time.
posted on June 1, 2020 
math
probably only a hundred books or so, and 100/4 = 25 So, a reasonable breakdown would be 3/4 = 75/100 nonfiction
posted on June 1, 2020 
Mathematics
as written, it is not true. I think you meant (1sin2x)/cos2x = (1  2sinx cosx)/(cos^2x  sin^2x) = (cos^2x  2sinx cosx + sin^2x)/(cos^2x  sin^2x) = (cosxsinx)^2 / ((cosxsinx)(cosx+sinx)) = (cosxsinx)/(cosx+sinx) = (1tanx)/(1+tanx) = tan(π/4  x)
posted on June 1, 2020 
Precalculus
it hits the ground when the height is zero, right? So just solve 6 + 95 sin25° t  16t^2 = 0
posted on June 1, 2020 
Precalculus
Assuming down the alley toward the pins is the +y direction, then (x,y) = 7*1.5 * (cos87,sin87)
posted on June 1, 2020 
precalculus
note that x^2+y^2 = 9 now review how angles are graphed in polar coordinates.
posted on June 1, 2020 
Math
find the limit of (f(x+h)f(x))/h = [((x+h)^2  3(x+h) + 5)  (x^23x+5)]/h You should wind up with 2x3
posted on June 1, 2020 
math
compare 7:5 to 40:30 or, 70:50 to 4:3 the size of the ratio says nothing about the total quantities
posted on June 1, 2020 
math
alternate signs as in ,,+,+,,,+,+,... and just keep multiplying by 4 a_n = (1)^(1+[(n1)/2] * 6 * 4^(n1) where [x] is the greatest integer (floor) function
posted on June 1, 2020 
math
r:b = 5:6 b:g = 3:4 = 6:8 r:b:g = 5:6:8 = 10:12:16 and so on there are many ways to do this, just multiplying those three numbers by any desired value
posted on June 1, 2020 
Mathematics
K/4650 = 3/5 now just solve for K
posted on June 1, 2020 
chemistry
M = mol/L so you are correct.
posted on May 31, 2020 
Science
compare 0.12 * 150 with 0.15 * 120 And a question cannot be true or false  it is a question.
posted on May 31, 2020 
math
oops. no math is required. I figured how many slices were eaten... There were 12 slices, and 5 are left. So, 5 bags needed.
posted on May 31, 2020 
math
12/12  5/12 = ___/12
posted on May 31, 2020 
math
Matt's score ... m 23 less than m ... m23 is ... = and so on.
posted on May 31, 2020 
math
a) your answer is correct, but you have an extra paren in lin e 3. (1^2  (3(1)+5)/(12) should be (1^2  3(1) + 5)/(12) b) is also correct
posted on May 31, 2020 
Algebra
(a^2a^4)÷a^−3 = (a^2a^4)*a^3 = a^6*a^3 = a^9 a/(a^2a^3)^4 = a/(a^5)^4 = a/a^20 = a^19 a^9÷a^19 = a^9 * a^19 = a^28
posted on May 31, 2020 
Mathematics
If you don't have a protractor, it is easy to construct the 105° angle, since 105=90+15 So just make a 90° angle make a 60° angle and bisect it twice to get the 15° angle Then add them together.
posted on May 31, 2020 
Math
Hard to parse your table. Are the first six values x and the last 5 y? Why are there not 12 values? As a first guess, I'd say the next x is 4, since the differences go 12, 6, 12, 6 The y differences go 12, 4, 12, 4 The extra ? stumps me.
posted on May 31, 2020 
Mathematics
(a) less improvement as just a number of points, or as a percentage? points: 30 > 18 percent: 18/30 > 1/2 30.60 = 1/2 (b) E+M(E&M) = U7 38+M9 = 63 Now you can answer the questions.
posted on May 30, 2020 
mathematics
well, S720E is just S so what is 20° less than S? S = 180°, so 18020 = 160°
posted on May 30, 2020 
math
c+a = 292 1.50c + 4.00a = 838.00 Now just solve for c and a.
posted on May 30, 2020 
mathematics
p= 1.8cm If you meant P, then use the law of cosines p^2 = q^2 + r^2  2qr cosP
posted on May 30, 2020 
mathematics
recall the law of sines sinA/a = sinB/b Once you have A, then C = 180(A+B)
posted on May 30, 2020 
mathematics
just add or subtract 180°, so that your answer is between 0 and 360°
posted on May 30, 2020 
Physics
I think I'd go with E. google turned up the following explanation: Note that as a group, the unsaturated fatty acids have lower melting points than the saturated fatty acids. The reason for this phenomenon can be found by a careful consideration of
posted on May 30, 2020 
Algebra
a_1 = 1/2 a_2 = 3/4 a_3 = 21/16 Now, since x^2+x > x^2 and a_n > 1 for n > 2 and (x^2+x/x) = x + 1 a_4/a_3 > a_3+1 = 37/16 > 3/2 The a_n are always increasing, and since a_3 >3/2, a_n > 5/2 for all n > 3 And, a_(n+1)/a_n = a(n) + 1 > 3/2 So, even though
posted on May 30, 2020 
Mathematics
#1) 181+142+117(75+60+54)+x = 200 I suspect a typo.
posted on May 30, 2020 
Math
800 cos39° you decide whether that's east or west. It won't be both...
posted on May 30, 2020 
Math
depends on the size of the walls ... double the area and divide by 100 to find the quarts needed (round up)
posted on May 30, 2020 
algebra
a+b = 2 ab = 4 add the two lines and you get 2a = 2 and the rest is easy.
posted on May 30, 2020 
math
again?
posted on May 30, 2020 
Algebra
In vertex form, f(x) = a(xh)+k where the vertex is at (h,k) f(x)=2/5x^24x+14 = 2/5 (x^2  10x) + 14 = 2/5 (x^2  10x + 25) + 14  2/5 * 25 = 2/5 (x5)^2 + 4 So the vertex is at (5,4) as above
posted on May 29, 2020 
Algebra
Just as a shortcut, for nPk, start at n and count down for k factors. For example, 9P3 = 9*8*7 for combinations, do the same, but divide by k factors counting up 12C4 = (12*11*10*9) / (1*2*3*4) Note that this makes it clear why you never have to go more
posted on May 29, 2020 
physics
v = fλ = λ/t so you are correct
posted on May 29, 2020 
Algebra
#1: 6/20 * 5/19 * 4/18 = 1/57 #2 chance of (brown,orange,orange) = 5/20 * 2/19 * 1/18 but the brown can happen in any of three places, so the final probability is 3(5/20 * 2/19 * 1/18) = 1/228 Too bad you couldn't be bothered to show your work  just
posted on May 29, 2020 
Math
well, that would be 40% of 26, right? 0.40 * 26 = ____
posted on May 29, 2020 
Math
looks good to me.
posted on May 29, 2020 
Math
rats  y = √33
posted on May 29, 2020 
Math
in QIII, x
posted on May 29, 2020 
Math
your calculations are correct, but that is not C
posted on May 29, 2020 
math
3 points for every field goal points depends on goals, right?
posted on May 29, 2020 
math
no diagram
posted on May 29, 2020 
math
divide both sides by nR
posted on May 29, 2020 
math
well, how many weeks is that? multiply that by 1/3 * $25
posted on May 29, 2020 
Algebra
since (a+b)^2 = a^2 + 2ab + b^2, we have (2√5+3√7)^2 = (2√5)^2 + 2(2√5)(3√7) + (3√7)^2 = 4*5 + 12√5√7 + 9*7 = ...
posted on May 29, 2020 
Calculus/Vectors
recall that T = rFsinθ so plug in your numbers
posted on May 29, 2020 
mathematics
They all say the same thing (D only if you already know A or B or C) I like C simpler than fractions, and the raw numbers in D really don't convey any information.
posted on May 29, 2020 
math
v = dy/dx = dy/dt / dx/dt = (e^t2cost)/(1/t + 3t^2) a = dv/dx = dv/dt / dx/dt = [(e^t+2sint)(1/t + 3t^2)  (6t  1/2)(e^t2cost)]/(1/t + 3t^2)^3 This is just a stupid exercise  needlessly complicated.
posted on May 29, 2020 
Algebra
again? 4√6/√30 * √30/√30 = 4√180/30 = 4*6√5/30 = 4√5/5 or 4√6/√30 = 4√6 / √5√6 = 4/√5 = 4√5/5
posted on May 29, 2020 
Physics
net force is the sum of all the forces acting on the object. Then, of course, F = ma if there is a nonzero net force, the object will undergo an acceleration.
posted on May 29, 2020 
Physical Science
assuming the pressure remains the same, V1/T1 = V2/T2 not sure how going from 1.2 cm^3 to 200 cm^3 is a decrease, though ...
posted on May 29, 2020 
Maths
red: P(male) = 1/3 blue: P(female) = 1/3 so, 1/9 that he will get both the needed gp's.
posted on May 29, 2020 
math
HCF(64,124) = HCF(4*16,4*31) = 4 LCM(64,124) = 64*124 / HCF(64,124)
posted on May 29, 2020 
precalculus
use the law of sines: b/sinB = a/sinA
posted on May 29, 2020 
mathematics
(h1.7)/25 = sin30°
posted on May 29, 2020 
Trig
tan>0 and cos
posted on May 28, 2020 
Algebra
See if you can show that a_(n+1) > 3/2 a_n Having that, now you know that 1/(a(n+1)+1) < 1/a(n+1) < 2/3 1/a_n That means that each term of the sum is less than the corresponding term in the geometric sequence a = 2/3 r = 2/3 The infinite sum of that is
posted on May 28, 2020 
science
what kind of magazine?
posted on May 28, 2020 
algebra
red = a white = a/2 total = a + a/2 = 3/2 a
posted on May 28, 2020 
Calculus
a×b ⊥ a and b c = {3, 5, 4}×{3, 1, 5} = {21,27,18} and of course, c is also ⊥ to a and b
posted on May 28, 2020 
Calculus
just plugging the various values for n, I get sum(1..∞) = ln 2 = 0.69314718 so we want the sum to lie between 0.69304 and 0.69324 sum(1..9) = 0.7456 sum(1..99) = 0.6981 sum(1..999) = 0.6936 sum(1..9999) = 0.693197
posted on May 28, 2020 
Calculus
so, did you use the table? It will probably provide a reduction formula, such as ∫x^n e^ax dx = 1/a x^n e^ax  n/a ∫ x^(n1) e^ax dx this is achieved using integration by parts. So, going through that three times gives you (1/9 x^3  1/27 x^2 + 2/243 x
posted on May 28, 2020 
math
P: (x,y) → (x,b(yb)) = (x,2by) Q: (x,y) → (x,2ay) P∘Q: (x,y) → (x,2a(2by)) = (x,2a2b+y)
posted on May 28, 2020 
Algebra
for any x, x + 6x = 7x You just happen to have x = sqrt5
posted on May 28, 2020 
Algebra
I assume you mean y = 1/2 x  3 So, just pick two values for x, say, 0 and 1, and figure what y is for each.
posted on May 28, 2020 
Maths
let P = (m,15/8 m) Q = (n,3/10 n) Then since PR=QR, (8m)^2 + (6  15/8 m)^2 = (8n)^2 + (6  3/10 n)^2 and, since the slope of PR = slope of QR, (15/8 m  6)/(m8) = (3/10 n  6)/(n8) Solving for m and n, we have m = 32/7, n = 80/7 Plugging that into the
posted on May 28, 2020 
Math
yes. after removing the parentheses, that would be the same as adding 7x+123x^2
posted on May 28, 2020 
geometry
adjacent angles are supplementary  they add to 180°
posted on May 28, 2020 
math
1030/95 = ____
posted on May 28, 2020 
Algebra
just subtract 4 from each element of the domain
posted on May 27, 2020 
mathematics
I'd guess nonnegative integers (up to some reasonable maximum)
posted on May 27, 2020