Answer: 310 centimeters square of paper
Explanation: to find the answer you need to know the surface area of the box. So you use the formula SA = 2ab+2bc+2ac
A=7
B=10
C=5
After inputting the values you get:
SA = 2(7)(10) + 2(10)(5) + 2(7)(5)
and after simplifying:
SA = 140+100+70
SA=310
Split up the integration interval into 4 subintervals:
![\left[0,\dfrac\pi8\right],\left[\dfrac\pi8,\dfrac\pi4\right],\left[\dfrac\pi4,\dfrac{3\pi}8\right],\left[\dfrac{3\pi}8,\dfrac\pi2\right]](https://tex.z-dn.net/?f=%5Cleft%5B0%2C%5Cdfrac%5Cpi8%5Cright%5D%2C%5Cleft%5B%5Cdfrac%5Cpi8%2C%5Cdfrac%5Cpi4%5Cright%5D%2C%5Cleft%5B%5Cdfrac%5Cpi4%2C%5Cdfrac%7B3%5Cpi%7D8%5Cright%5D%2C%5Cleft%5B%5Cdfrac%7B3%5Cpi%7D8%2C%5Cdfrac%5Cpi2%5Cright%5D)
The left and right endpoints of the 
-th subinterval, respectively, are
for 
, and the respective midpoints are
We approximate the (signed) area under the curve over each subinterval by
so that
We approximate the area for each subinterval by
so that
We first interpolate the integrand over each subinterval by a quadratic polynomial 
, where
so that
It so happens that the integral of reduces nicely to the form you're probably more familiar with,
Then the integral is approximately
Compare these to the actual value of the integral, 3. I've included plots of the approximations below.
Problem:
Solve
2
x
+
5
y
=
−
3
;
3
x
−
y
=
21
Steps:
I will try to solve your system of equations.
3
x
−
y
=
21
;
2
x
+
5
y
=
−
3
Step: Solve
3
x
−
y
=
21
for y:
3
x
−
y
+
−
3
x
=
21
+
−
3
x
(Add -3x to both sides)
−
y
=
−
3
x
+
21
−
y
−
1
=
−
3
x
+
21
−
1
(Divide both sides by -1)
y
=
3
x
−
21
Step: Substitute
3
x
−
21
for
y
in
2
x
+
5
y
=
−
3
:
2
x
+
5
y
=
−
3
2
x
+
5
(
3
x
−
21
)
=
−
3
17
x
−
105
=
−
3
(Simplify both sides of the equation)
17
x
−
105
+
105
=
−
3
+
105
(Add 105 to both sides)
17
x
=
102
17
x
17
=
102
17
(Divide both sides by 17)
x
=
6
Step: Substitute
6
for
x
in
y
=
3
x
−
21
:
y
=
3
x
−
21
y
=
(
3
)
(
6
)
−
21
y
=
−
3
(Simplify both sides of the equation)
Answer:
y
=
−
3
and
x
=
6
Zoom in I think I know this
Answer:
I = (70) x (0.03) x (12)
Step-by-step explanation:
The general formula of simple interest formula is: I = PRT where I = simple interest, P = principal amount, R = interest rate, T = time (in years). Given that the initial investment is $70, the interest rate is 3% (or 0.03 as a decimal) and the time is 12 years, you can form the following:
I = (70) x (0.03) x (12)
