MaxWong

200 + 10 + | r 2 = 210 + | r 2.

I can not recognize the last bit of the question

Hi Melody :D It has been long since my last login 

$\frac{7}{6}\times \frac{8}{7} \times ...... \times \frac{40}{39}= \frac{40}{6}= \frac{20}{3}$

The numerator of the n-th fractions just cancels out with the denominator of the (n+1)-th fractions

0.0059 - (- 0.0096)

= 0.0155

$\quad\frac{4}{3}\times\frac{22}7\times8 ^3\\ = \frac{4}{3}\times\frac{22}7\times512 \\ = \frac{45056}{21} \space or \space 2145\frac{11}{21}$

400 x 100  x 2  x  4  x  10  x  4000  x  50 = 640000000000

Left hand side = 2

Right hand side =$-\frac{1}{8(-1-2)^3}-1= -\frac{1}{-216}-1=-\frac{215}{216}$

The 2 sides isn't the same

$h=\frac{-b}{2a}\\ 2ah=-b\\ b=-2ah$

$1. \quad |F_E|=k|\frac{q_1q_2}{r^2}|\\|\frac{F_E}{k}|=|\frac{q_1q_2}{r^2}|\\\frac{F_E}{k}=\frac{q_1q_2}{r^2}\\ q_1=\frac{(F_E)(r^2)}{kq_2}\\ Correct.$

2nd question. Too lazy to type in LaTeX. Correct.

3rd question Correct.

Yes.

0.0000000062715585 corrected to 1 dp = 0

0.0000000062715585 corrected to 2 dp = 0

......

0.0000000062715585 corrected to 7 dp= 0

0.0000000062715585 corrected to 8 dp= 0.00000001

0.01 corrected to 1dp = 0