Given:
The initial mass of an element is 800 grams.
Decay rate = 8.2% per day
Number of days = 15
To find:
The remaining element after 15 days.
Solution:
The exponential decay model is
Where, a is the initial value r is the rate of interest and t is time period.
Putting 
in the above formula, we get
Therefore, the mass of the remaining element is 221.7 grams.
It is 4009.738/!;7 corrects
15x2+10x-9x+7
8x3+20x2+3x+12
11x4+4x2-6x2-16
Hope this helps !!
Answer:
x= -2.........&.........y= -1
Step-by-step explanation:
(x,y)=(-2,-1)
tan2x*cotx - 3 = 0
We know that: tan2x = sin2x/cos2x and cotx = cosx/sinx
==> sin2x/cos2x *cosx/sinx = 3
Now we know that sin2x = 2sinx*cosx
==> 2sinxcosx/cos2x * cosx/sinx = 3
Reduce sinx:
==> 2cos^2 x/ cos2x = 3
Now we know that cos2x = 2cos^2 x-1
==> 2cos^2 x/(2cos^2 x -1) = 3
==> 2cos^2 x = 3(2cos^2 x -1)
==> 2cos^2 x = 6cos^2 x - 3
==> -4cos^2 x= -3
==> 4cos^2 x = 3
==> cos^2 x = 3/4
==> cosx = +-sqrt3/ 2
<span>==> x = pi/6, 5pi/6, 7pi/6, and 11pi/6</span>
