Answer:
C
Step-by-step explanation:
An approximation of an integral is given by:

First, find Δx. Our a = 2 and b = 8:

The left endpoint is modeled with:

And the right endpoint is modeled with:

Since we are using a Left Riemann Sum, we will use the first equation.
Our function is:

Therefore:

By substitution:

Putting it all together:

Thus, our answer is C.
*Note: Not sure why they placed the exponent outside the cosine. Perhaps it was a typo. But C will most likely be the correct answer regardless.
Answer:
x = 3, y = 6
Step-by-step explanation:
In the figure attached,
If ΔADE and ΔABC are similar triangles, their corresponding sides will be in the same ratio.
By this property,




3x = 2x + 3
3x - 2x = 3
x = 3
Similarly, 

y = 
y = 6
If B is the midpoint of AC, then AB=BC. It is also BC=AC-AB
AB = x + 6
AC = 5x - 6
BC = (5x - 6) - (x + 6)
We can kinda use distributive property, like this:
BC = 5x - 6 -x - 6
Combine like terms:
BC = 4x - 12
To verify, we can add AB and BC to see if their sum is equal to AC.
(x + 6) + (4x - 12) = 5x - 6
If we are correct, this equation will be true.
x + 6 + 4x - 12 = 5x - 6
Combine like terms:
6 + 5x - 12 = 5x - 6
5x - 6 = 5x - 6
It's correct!
BC = 4x - 12. Final Answer.
Let me know if you have any questions about this! :)
B 12:3 = 4-1=3 C 10- 7=3 And A 2+15x=x=15-2=13