ElectricPavlov

6 +  1 divided by 6 = 6.16666666...

Area Circle =  pi x r^2

area/pi  = r^2

sqrt( area/pi) = r 

For a lot of calculations it IS a rough approximation and usually suffices.

22/7 = 3.142857

pi=      3.141592....      See  how close they are?     

For adding and subtracting fractions you MUST have a common denominator (not so when dividing or multiplying)

denominators   10  12 and 3   have a common denomintor of 60

3/10 x 6/6 = 18 /60

3/12 x 5/5 =  15/60

2/3 x 20/20 = 40/60

18/60 + 15/60 + 40/60 = 73/60= 1 13/60

561 is approximatly 2 standard deviations from mean:  530 +  (2 x 15)....if you look at a bell curve this is the upper 2% of lightbulbs

so probability is   2/100   or  1/50  

3/8   IS  a fraction

3/8 = .375   as a decimal

-3  determines the amplitude      cos goes from -1 to 1    the subtract one at the end of the equation shift the graph DOWN  1

-3  to 3      then shift down ONE   -4  to  2 is the min  and max

(2(x-pi/4)    

  the 2   will increase the frequency by a factor of 2    the pi/4 will shift the graph to the right (.785398 radians)

(I think)

I am not  ABSOLUTELY positive of these answers...I saw this question was not answered yesterday, so I took a stab at it today.

If you go to desmos graphing calculator , you can confirm all of this !   

Anyone else?

'UNDEFINED'      .....   you cannot divide by ZERO

-3^4  =  -3 x -3 x -3 x -3 = + 81

1/3    is pretty simple