Sunday
June 26, 2016

Posts by steve

Total # Posts: 41,433

math(bearing)
There seems to be a lot of noise here If the bearing of Y from Z is 280, then the bearing of Z from Y is 280-180 = 100
June 8, 2016

Pre-Cal (Help Plz)
come on. x^2-4 is negative on the interval (-2,2) So, since |x^2-4| is always positive, that little arc below the x-axis is flipped up above it. Everywhere else, the two functions are identical. g(x) = -f(x) if |x| < 2 g(x) = f(x) if |x| >= 2
June 8, 2016

Pre-Cal (Help Plz)
take a look at the graphs and see what you can say. And why not use || for absolute value? It's not like you don't have the characters... http://www.wolframalpha.com/input/?i=plot+y%3Dx^2-4,+y%3D|x^2-4|
June 8, 2016

math
ok
June 8, 2016

Trigonometry
off course as measured how? Actual distance between target and position, or distance perpendicular to the intended course? In the first case, use the law of cosines. Both sides of the included angle are 152*2
June 8, 2016

Trigonometry
draw the diagram. It should be clear that if the height is h, h cot32° - h cot40° = 12
June 8, 2016

Trigonometry
draw the diagram. It should be clear that north: 83 cos37° west: 83 sin37°
June 8, 2016

math
looks good to me.
June 8, 2016

Math - eh?
NO IDEA! Where the heck is X?
June 8, 2016

PreAlgebra
x^2 = 22^2 - 7^2 now just crank it out
June 8, 2016

Math
your formula is correct, but your answer is not. Oh, well.
June 8, 2016

Math
a = 2πr(r+h) = 2π(9)(9 + 19) = 504π So, D How did you get 523?
June 8, 2016

Math
yes, it is correct.
June 8, 2016

Science
PV/T is constant, so you want T such that 1.82*18.7/353 = 1.41*25.1/T T ≈ 367
June 8, 2016

aptitude
clearing fractions and decimals, we have 125x + 5y = 21 3x + y = 3 now you can substitute y = 3-3x to get 125x + 5(3-3x) = 21 Now it's easy to solve for x, and then you can get y.
June 8, 2016

Algebra
Seems we want cube roots: ∛540r^3 s^2 t^9 = ∛27*20 r^3 s^2 (t^3)^3 = 3rt^3 ∛20s^2 so, yes, you are correct
June 8, 2016

maths
just plug in values for t: x(2) = 16*2 - 2*2^2 = 32-8 = 24 likewise for t=6
June 8, 2016

math
starting with 1, after chocolates, 3/5 remains after gift to sister, she has 8/9 * 3/5 = 8/15 after books, she has 1/4 * 8/15 = 2/15
June 8, 2016

Math
so, which ones did you get? Show some work, eh? This is a massive homework dump. And sorry, you will have to describe the graphics is possible.
June 8, 2016

Trigonometry
as usual, with fractions, cross-multiply, and you will see one of your standard identities.
June 8, 2016

Trigonometry
I assume you mean 4sin^2(3θ) - 3 = 0 sin^2(3θ) = 3/4 sin(3θ) = √3/2 3θ = 60° or 120° θ = 20° or 40° Since sin(3θ) has period 360/3 = 120°, add multiples of 120° to those values. You will find six solutions in the ...
June 7, 2016

Trigonometry
you have tanx = -2 so, the solutions will be in QII and QIV.
June 7, 2016

Trigonometry
since sin^2x = 1 - cos^2x, make that substitution, and then solve the quadratic for cos(x)
June 7, 2016

Trigonometry
No idea what a double identity is, but draw the triangle. The missing side is √24. In QII, that means x is negative, so cosθ = x/r = -√24/5 cotθ = x/y = -√24/1
June 7, 2016

math
clearly the major axis has length 13, and the minor axis has length 12. So a = 13/2 b = 6 c^2 = a^2-b^2 = 25/4, so c = 5/2 The center is at (13/2,0), so h = 13/2 and k=0 The foci are at (h±c,k) Since the major axis is horizontal, that means the equation is (x-h)^2/a^2...
June 7, 2016

Math
so, no, A is not correct.
June 7, 2016

math
a = 0.9 o so, o = a/0.9 = 1.111a so, the orange is 11% heavier than the apple. The grapefruit is just noise.
June 7, 2016

math
do you even look at what you type? That's "sides" not "size"! and "menion" just escapes me totally! If the two diagonals are x and y, then using the law of cosines, and the fact that consecutive angles are supplementary, x^2 = 6^2+9^2 - 2*6*9 ...
June 7, 2016

Algebra
It sounds like you want a recursive sequence, where T(n+1) = 4Tn - Tn^2 If so, then if Tn = 4*2.4 - 2.4^2 = 3.84 T(n+1) = 4*3.84 - 3.84^2 = 0.61
June 7, 2016

math
5000*1.01^8 + 10000*1.01^16
June 7, 2016

Math Help Please
Note which side is opposite to A and adjacent to A. Now review your basic trig functions. You can see that sinA = BC/AB cosA = AC/AB so you are correct. Extra credit: How did I figure it out, with no triangle to refer to?
June 7, 2016

value
you don't move on a bearing. You move on a heading. You observe on a bearing. Starting from R at (0,0), P moves to (-20/√2,-20/√2) Q moves to (15√3/2,15/2) now just find the distance between those points. Or, use the law of cosines. The angle between ...
June 7, 2016

algebra
12 mg / kg * 1kg/2.2lb * 120lb = 655mg
June 7, 2016

maths
What do you mean when you say when it is perpendicular to it ?? when what is perpendicular to what?
June 7, 2016

Maths
1+1 = 2 You have some other questions?
June 7, 2016

Maths
DBA = BDC = 28° DBC = 90° - DBA = 62°
June 7, 2016

Math (money)
(x - 200)(.80) - 131 = .20x x = 485 check: start: 485 dress: 200 leaves 285 bag: 57 leaves 228 shoes: 131 leaves 97 = 20% of 485
June 7, 2016

MATH - ??
Ouch! I got confused on the period/comma usage disparity. Or, I could just say I was figuring in km instead of meters!
June 7, 2016

MATH
x(1 - 1/3 - 2/5) = 6/5 4/15 x = 6/5 x = 9/2 check: 1/3 of 9/2 = 3/2 = 1.5 2/5 of 9/2 = 9/5 = 1.8 1.5 + 1.8 + 1.2 = 4.5 = 9/2
June 7, 2016

maths
if cos3Q = √3/2, sin3Q = ±1/2 so, tan3Q = ±1/√3 so, using the +1/2 value, tan6Q = 2tan3Q/(1-tan^2 3Q) = 2(1/√3)/(1 - 1/3) = (2/√3)/(2/3) = 3/√3 = √3 so, -√3 if sin3Q = -1/2
June 7, 2016

Math (Trig)
right on
June 7, 2016

Maths
200 trees means 199 intervals between. So, each interval is 396/199 meters. That means that the nth tree is at a distance from the first of Tn = (n-1)(396/199) Now just plug in 15 for n and you have your distance.
June 6, 2016

math
well, you could start off by writing that with math symbols: 2x/5 = 12 Now just solve for x.
June 6, 2016

Math
that equation describes a line. Was there something in particular you wanted to know about it? Getting rid of the fractions, it could also be written as 7x + 90y + 72 = 0
June 6, 2016

Math
not quite. It was simple interest, not compound. 4300(1+.018*15) = 5461.00
June 6, 2016

Math
well 40° is 1/9 of 360°, or the whole pizza.
June 6, 2016

Math
Draw a N-S line through A. From that line, the angle back to the start is 55°, and the angle to B is 64° 55+64 = 119 That means the interior angle must be 61°, since the entire N-S line is a straight angle.
June 6, 2016

Math (*-*)
a larger denominator means a smaller value. Think about it. If you cut a pizza into 4 pieces, 7 pieces, 10 pieces, which pieces are smaller?
June 6, 2016

Math
see related questions below
June 6, 2016

trade science
do you know the thermal expansion coefficient?
June 6, 2016

math @Reiny
I think I like your thinking. Sorry, danbaba.
June 6, 2016

math
(ii) 2/3 * 1/3 (i) 1 minus that
June 6, 2016

Maths
well, that would be 9*20000 cm Just change that to km or, to make things easier, 20000cm = 200m = 0.2km so, 9cm = 9*0.2 km
June 6, 2016

7th Grade Math
sorry that should be (a+b)/2 * h
June 6, 2016

7th Grade Math
There is missing information. You cannot get the area of the triangle without knowing its height. Then its area is 1/2 * base * height The area of a rectangle is width * height A trapezoid has two bases and a width (or height) -- you only name one. Then, a trapezoid with bases...
June 6, 2016

7th Grade Math
So, how did you get the area of 46 without finding the areas of the three shapes? You do know how to do those, I guess? Just show your work so the teacher knows you can do the areas. Why not show your work here, so we can see what's going on... Also, area is square inches...
June 6, 2016

math
draw the two triangles in standard position. A is a 5-12-13 triangle, and B is 8-15-17. sinA = 5/13 cosA = 12/13 tanA = 5/12 sinB = 8/17 cosB = -15/17 tanB = -8/15 Now just plug those values into your addition formulas for the trig functions.
June 6, 2016

MATHS
what, you can't plug in the digits and add? EGG+EGG = 899+899 and so on
June 6, 2016

Maths
well, what is 3/5 of 20? No idea? what is 1/5 of 20? ...
June 6, 2016

abc
since distance = speed * time, if Ashok's speed is a, and thw wind's is w, then we have (3/2)(a+w) = 60 (2)(a-w) = 60
June 6, 2016

math
Did you try actually plotting the line segment? Just plot (1,2) and then go 5 left and 5 right. A=(-4,2) B=(6,2)
June 6, 2016

math
hint: gradient 0 means y never changes.
June 6, 2016

uncc
x: 15 cos30 y: 15 sin30
June 6, 2016

Math
s = 1/2 at^2 = 1/2 t^(5/2)
June 6, 2016

Pre-Calc
sorry; the heading is 34.02° (It's 90-A), not 90+A
June 5, 2016

Pre-Calc
630 @ 𝑁 30° 𝐸 = <315.00,545.58> wind from the SE is in the direction NW, so 45 @ NW = <-31.82,31.82> Now, if the plane's ground speed is <x,y> we have <x,y> + <-31.82,31.82> = <315.00,545.58> x = 346.82 y = 513.76 ...
June 5, 2016

Pre-Calc
just convert the vectors to x-y components, add them, and you have the resultant. Can you get that far? If not, where do you get stuck?
June 5, 2016

11
Check your sum-to-product formulas. I expect it will fall right out.
June 5, 2016

maths,science, physics
just preserve momentum: (420)(-30) + (200)(30) = (420+200)(v) v = -10.65
June 5, 2016

maths-calculus help me
d/dx arccosh(u) = 1/√(u^2-1) so d/dx arccosh(x^2+1) = 1/√((x^2+1)^2-1) * 2x if y = arcsinh(x^2), dy/dx = 1/√(x^4+1) * 2x Not quite sure just what it is you are trying to do.
June 5, 2016

Math2
Draw a diagram. You have a pyramid with base ABC and summit at S. I am assuming that S is at the top of a vertical face containing BC. You have base angles A = 80 B = 61 so, C=39 side c = 400 So, now you can figure sides a and b using the law of sines. Hmm. Still can't pin...
June 5, 2016

Math
you have an isosceles triangle with both base angles 89.9° The base of the triangle is the diameter of earth's orbit. Knowing that, you can find the altitude of the triangle (the distance to the object).
June 5, 2016

physics
tanA = y/x = 29.0/-96.0 Note that it is in QII
June 5, 2016

Vectors
Your angle of 21.5° is right, but if you draw the diagram, you will see that the bird is roughly NW, so it must fly roughly SE. So, it is really -21.5° (relative to the x-axis), or a heading of 111.5° from due North.
June 5, 2016

Vectors
the distance d is found by d^2 = (4.8-1.5)^2 + 1.3^2
June 5, 2016

physics
acceleration = 20m/s ÷ 10s = 2 m/s^2 deceleration takes twice as long, so it is half as much.
June 5, 2016

physics
surely you have a formula which gives this value. If not, see the excellent article in wikipedia on "trajectory"
June 5, 2016

Math
MP*.84 = CP*1.05 MP/CP = 1.05/0.84 = 1.25 so, the original markup was 25%
June 5, 2016

MATH
Draw a diagram. It is clear that the distance of chord from center: d^2 + (6/2)^2 = 5^2 the chords are 2d apart.
June 5, 2016

maths
18*2 + x = 27*3
June 5, 2016

itc c++
what, you don't have a c++ system?
June 5, 2016

math
The beam length b is b^2 = 192^2 + (70+10)^2
June 5, 2016

Math - surface area
well, the area is πr^2 = 4π yd^2 a first approximation is thus 4π*13
June 5, 2016

maths
24^2 + 48^2 + h^2 = 56^2
June 5, 2016

math
3b+c = 14t b+6t = 1c so, find c in terms of t: c = 14t-3b = 14t-3(c-6t) c = 14t-3c+18t 4c = 32t c = 8t
June 5, 2016

math
If the 4 groups have w,x,y,z respectively, then w = x+4 x = y-1 z = 2x w+x+y+z = 20 Now just crank it out.
June 5, 2016

Math(Please Help Assignment Due Today)
man. of all the possible sets, AAA does not guarantee congruence -- only similarity.
June 4, 2016

Math(Please Help Assignment Due Today)
well, you've posted this a few times. Did you think of googling your question? Many hits. Maybe you could start here: http://www.regentsprep.org/regents/math/geometry/gp4/ltriangles.htm
June 4, 2016

math
not quite. You figured the straight-line distance, but that does not answer the question. Read it again carefully.
June 4, 2016

physics
The ratio of KE after the bounce to before the bounce is 1/2 m(.8v)^2 -----------------      1/2 mv^2 = .8^2 = .64 so, the ball will bounce .64 as high as the original height
June 4, 2016

geometry
so, add 5 to x and subtract 4 from y. Not so hard, eh?
June 4, 2016

maths
f(x) = 2x Looks like y= ax, with a=2 or y = 2f(x) if f(x) = x not quite sure just what it is you're asking. enter your expression at wolframalpha.com and see the graph.
June 4, 2016

science
the difference is .11 hours .11/3.15 = 0.0349 ≈ 3.5%
June 4, 2016

mathematics
As always, draw a diagram. AB/18 = tan35° CD^2 = 18^2 + 24^2 from C, tanθ = AB/24 from D to C, tanθ=24/18, so the bearing is 360-θ
June 4, 2016

mathematics
well, the common denominator is 2(y-1), so that gives you 1(y-1)+3(2) -----------------     2(y-1) ...
June 4, 2016

Math
but, you know how to count money, right? 7 quarters = $1.75 need 11 more coins, so start using smaller ones. 6 quarters and 5 nickels = $1.75 need 7 more coins 5 quarters and 10 nickels = $1.75 need 2 more coins. 4 quarters and 15 nickels - $1.75 need 2 coins less 4 quarters, ...
June 4, 2016

Math-Calc
so, the critical numbers are the values where f'(r) = 0, right? A fraction is zero if its numerator is zero. So, what is r if 7 - 10r^2 = 0?
June 4, 2016

Statistics
Never mind -- I'm bored already.
June 4, 2016

maths again plz
since 1 hour is 60 minutes, 35'25" = 0.59 of a complete circle. the circumference is 2pi*r, so the distance traveled is 2pi*8.8*0.59 = 32.64 cm
June 3, 2016

maths-need help asap
yes, with no radius, it's difficult to find the volume. The problem has been garbled, apparently. Both the cylinder and the cone are incompletely specified. And that doesn't even get into the bad grammar...
June 3, 2016

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