Saturday
April 30, 2016

# Posts by black_widow

Total # Posts: 47

chemistry
How to compare the melting point of two ionic bod or two covalent bond?
April 28, 2013

chemistry
why does MgO has a higher boiling and melting point than NaCl?
April 28, 2013

Math ( Polynomial )
by using long division, divide x^4-6x^3+16x^2-25x+10with x^2-2x+k, then you will find: remainder=(-9+2k)x +10-8k+k^2 comparing with x + a, -9+2k=1,k=5 a=10-8k+k^2,a=-5 therefore k + a=5-5=0
April 13, 2013

Maths
Is it correct?
April 12, 2013

Maths
My way of solving...... Let k=m+1 2^(m+1)-2^m <1000 2^m <1000 m<=9 therefore k<=10 For distinct value of k and m, when k=1, m=0 when k=2, m=0,1 when k=3, m=0,1,2 . . . when k=10 2^k−2^m<1000 2^10-2^m<1000 m>=4 no of possible value of m is 5 total ...
April 12, 2013

chemistry
is this mean that e/z notation can definitely explain cis-trans isomerism but cis-trans not necessary can explain e/z notation ?
April 12, 2013

chemistry
i have seen it but still dont understand.....
April 12, 2013

chemistry
What is the difference between e/z notation and cis-trans isomerism?
April 12, 2013

Maths
is it 3?
April 12, 2013

Math
sorry about that.... I thought 0 is neither even nor odd....
April 6, 2013

Math
Let a>b a=2n+1+2k ,n,k is positive b=2n+1 (a+b)/2=2n+1+k (a-b)/2=k If k is odd, then (a+b)/2 is even (a-b)/2 is odd If k is even, (a+b)/2 is odd (a-b)/2 is even The same method also applies if a<b (However I assume that a,b are distinct number because if a=b, (a-b)/2=0 ...
April 6, 2013

algebra
let x^(1/3)=a 6a^2-11a+4=0 a=0.5, a=4/3 x=1/8, x=64/27
April 1, 2013

maths
My answer is 440 My way of solving: xyz(z)=−64y−128x (1) xyz(x)=−32y−32z (2) 3xyz(y)=128x−64z (3) (1)-(2) xyz(z-2x)=64(z-2x) xyz=64 ,z=2x if z=2x,x=y=z=0 if xyz=64, sub xyz=64 into (1),(2),(3) simplify it and you can get: z=-y-2x (4) 2x=-y-z (5) ...
April 1, 2013

Algebra
f(x)=3x^2-21x+36 sum of roots =-(-21/3)=7
March 26, 2013

Algebra
sorry the answer should be 101 I do like this: first consider the possible last digit of the number, then you have 0,1,5,6 Let N be ab For number end with 0, the last two digits of N will be 00 no numbers can be formed as 00 is not a 2 digit numbers For number end with 1, it ...
March 26, 2013

Algebra
March 26, 2013

Collage Physics
The pull of cable is 5.24x10^3N The force exerted by the man =75N Is it correct?
March 26, 2013

GEOMetry(TRIANGLE)
Let length of AB =a sABC=sABD+sACD (s stands for area) 1/2x60x(a^2-30^2)^0.5=1/2x(16a+32a) 5(a^2-30^2)^0.5=4a 25a^2-16a^2=25x30^2 a^2=2500 a=50
March 25, 2013

Using the remainder
Given f(x)=2x^3-10x^2+11x+12 f(3)=2(3)^3-10(3)^2+11(3)+12 = 9 because f(3)not equal to 0 Therefore x-3 is not a factor of f(x)
March 24, 2013

Solve the inequality
x^2(8+x)(x-9)/(x+4)(x-7) >=0 x^2(8+x)(x-9)(x+4)(x-7)>=0 therefore the ranges are x>=9,0<=x<=7,-8<=x<=-4 But x cannot equal -4 or 7 therefore the ranges of x are x>=9,0<=x<7,-8<=x<-4
March 24, 2013

inequality
the range of x is x>4
March 24, 2013

Math (Number Theory)
1/a + 1/b + 1/c = 0 bc+ac+ab = 0 a^2 + b^2 + c^2 =(a+b+c)^2 -2(ab+bc+ac) =(11)^2-2(0) =121
March 24, 2013

maths
What is Mersenne prime?
March 24, 2013

maths
Solve the inequality //(2x-1)(x+3)/-4/< 1 where /x/ is the modulus of x.
March 24, 2013

maths
Is every Fermat number 2^(2^n) + 1 composite for n > 4?
March 23, 2013

University of Ghana
Average speed = (26+14+15+17)/2 km/h =36 km/h =36x1000/(60x60) m/s =10 m/s
March 23, 2013

maths
still cant solve it.....
March 23, 2013

maths
Solve the inequality //(2x-1)(x+3)/-4/< 1 where /x/ is the modulus of x.
March 23, 2013

maths
If G is a group of order 12, the G must have a subgroup of all of the following orders EXCEPT Choose one answer. a. 0 b. 12 c. 2 d. 3 e. 6 f. 4
March 23, 2013

maths
Let the bottom edge of a rectangular mirror on a vertical wall be parallel to and h feet above the level floor. If a person with eyes t feet above the floor is standing direct at a distance d feet from the mirror, what is the relationship among h,d and t if the person can just...
March 23, 2013

maths
What is the value of e^i(pi)? where i^2 =-1 ,e =exponential
March 22, 2013

maths
Prove : (a^2+b^2+c^2+d^2)(1/a^2+1/b^2+1/c^2+1/d^2)greater equal to 16
March 21, 2013

inequality- why is this wrong?
opps sorry made some calculation mistakes....
March 21, 2013

inequality- why is this wrong?
it should be x>-3
March 21, 2013

maths
Prove : (a^2+b^2+c^2+d^2)(1/a^2+1/b^2+1/c^2+1/d^2)greater equal to 16
March 17, 2013

maths
Given that a,b,c >0 Prove : (a/b + b/c +c/a)(b/a +c/b +a/c)>0
March 17, 2013

biology
Is pore protein = channel protein?
March 17, 2013

physics
March 16, 2013

physics
Impulse = change in momentum I= m(v-u) I=70.5 (5.85-0) I=412.4Ns
March 16, 2013

Physics
Consider only vertical component (because the object does not move horizontally) Use formula v=u+at v=0+9.8(7) v=68.6m/s
March 16, 2013

Calculas
is it x^3 -(2x+5)/(x+4) ?
March 16, 2013

Calculas
Is your question is f(x)= x^3-2x+(5/x)+4 ?
March 16, 2013

Physics
Yes the magnitude will be the same until the force exceed the maximum frictional force then the system will only move with an acceleration.
March 16, 2013

Physics
Let the magnitude of friction force = f acceleration ,a = 0 (because it moves with constant speed) F=ma 20-f=30x0 f=20N
March 16, 2013

physics
Let the resistive force = f F=ma 10-f=0.2x2 f=9.6N
March 16, 2013

math
Let 25x^2+(a−15)x+9=0 Discriminant B^2-4AC=0 (only one distinct root) (a-15)^2-4(25)(9)=0 (a-15)^2=900 a=15+30 or a=15-30 a=45 a=-15 therefore sum of a =45+(-15) a =30
March 15, 2013

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