Answer:
a) 

And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %
b) 

So one deviation below the mean we have: (100-68)/2 = 16%
c) 

For this case below 2 deviation from the mean we have 2.5% and above 1 deviation from the mean we got 16% and then the percentage between -2 and 1 deviation above the mean we got: (100-16-2.5)% = 81.5%
Step-by-step explanation:
For this case we have a random variable with the following parameters:

From the empirical rule we know that within one deviation from the mean we have 68% of the values, within two deviations we have 95% and within 3 deviations we have 99.7% of the data.
We want to find the following probability:

We can find the number of deviation from the mean with the z score formula:

And replacing we got


And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %
For the second case:


So one deviation below the mean we have: (100-68)/2 = 16%
For the third case:

And replacing we got:


For this case below 2 deviation from the mean we have 2.5% and above 1 deviation from the mean we got 16% and then the percentage between -2 and 1 deviation above the mean we got: (100-16-2.5)% = 81.5%
-72-4x^2+8x^3-36x/x-3
-4(18+x^2-2x^3+9x)/x-3
-4(-2x^3+x^2+9x+18)/x-3
-4(-2x^2x(x-3)-5x x(x-3)-6(x-3) )/x-3
-4 x(-(x-3) ) x (2x^2+5x+6)/x-3
-4 x (-1) x (2x^2 +5x+6)
8x^2+20x+24
Answer:
Step-by-step explanation:
Numerator
sin
x
cos
y
+
cos
x
sin
y
−
[
sin
x
cos
y
−
cos
x
sin
y
)
=
sin
x
cos
y
+
cos
x
sin
y
−
sin
x
cos
y
+
cos
x
sin
y
=
2
cos
x
sin
y
Denominator
cos
x
cos
y
−
sin
x
sin
y
+
cos
x
cos
y
+
sin
x
sin
y
=
cos
x
cos
y
−
sin
x
sin
y
+
cos
x
cos
y
+
sin
x
sin
y
=
2
cos
x
cos
y
---------------------------------------------------------------
left side can now be expressed as
2
cos
x
sin
y
2
cos
x
cos
y
=
2
cos
x
sin
y
2
cos
x
cos
y
=
sin
y
cos
y
and
sin
y
cos
y
=
tan
y
=
right side hence proved
The ratio would be 3:4, or however you write ratios.
Hope this helped! :)
2,5 * 10^3
25 * 10^2
0,25 * 10^4