The answer is C. I need a total of 20 characters so heres a smiley face:)
Answer:

Step-by-step explanation:
Given information: |a| = 80, |b| = 50, the angle between a and b is 3π/4.
We need to find the dot product a · b.
The formula of dot product is

where, θ is the angle between a and b.
Substitute the given values in the above formula.


![[\because \cos (\pi-\theta)=-\cos \theta]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Ccos%20%28%5Cpi-%5Ctheta%29%3D-%5Ccos%20%5Ctheta%5D)


Rationalize the above equation.



Therefore, the value of a · b is
.
Answer:
sec (x)
Step-by-step explanation:
sec (x) tan (x) cos (x) csc (x) =
We know sec = 1/ cos
Tan = sin/cos
csc = 1/sin
Replacing into the expression
1/ cos (x) * sin(x)/ cos (x) * cos (x) * 1 / sin(x)
Canceling like terms
1/ cos (x)
sec(x)
Answer:
27,000
Step-by-step explanation:
PLS GIVE ME BRAINLIEST