Wednesday
June 19, 2013

# Posts by Louis

Total # Posts: 103

Chemistry
If a sample of oxygen-15 has an activity of 8000 becquerels, how many minutes will elapse before it reaches an activity of 500 becquerels?

Mathematics
The difference between the x-coordinates of two points on the parabola y^2=4ax is fixed at 2k. Find the equation that describes the position(xp, py)of the point of intersection P of the tangents at the two points. The equation is in the form yp^2=f(xp). Hence show that 4axp<...

math
You may find it simpler to rotate the curve and the line a quarter turn anti-clockwise around the origin. This gives y = x^2/4 and y = 1/2x + 2 They intersect at x = -2 and 4. Find the definite integral over the interval (-2, 4) of 1/2x + 2 - x^2/4. This gives 9 units

Chemistry
What is the pH when 25 mL of .20 M CH3COOH has been titrated with 35 mL of .10 M NaOH?

chemistry
if i have a molar concentration of acetic acid.046 mol/L how do i get the calculated molar mass of acetic acid

10+10+0+0=20

College Geology Homework
Suppose you have a sample of potassium feldspar from a rhyolite and you measure the ratio of atoms of 40Ar to 40K of 0.024 to 1, or for every 10000 atoms of 40K you find 240 atoms of 40Ar. For this problem, consider the decline of 40K from an initial value to the measured valu...

calculus
Since the two tangents are mutually perpendicular and intersect on the y-axis they have gradients 1 and -1 The gradient function is y = 6x Hence x = 1/6, -1/6 So y = 1/12 both times So the coordinate of the intercept can be calculated using the equation of the tangents: Equate...

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