<h3>
Answer:</h3>
a. -(3√13)/13
<h3>
Step-by-step explanation:</h3>
The cosine can be found from the tangent by way of the secant.
tan(θ)² +1 = sec(θ)² = 1/cos(θ)²
Then ...
cos(θ) = ±1/√(tan(θ)² +1)
The <em>cosine is negative in the second quadrant</em>, so we will choose that sign.
cos(θ) = -1/√((-2/3)² +1) = -1/√(4/9 +1) = -1/√(13/9)
cos(θ) = -3/√13 = -(3√13)/13 . . . . . matches your selection A
Answer:
bhj vghvghvjvjvvvvvvvvvvvvv
Step-by-step explanation:
The answers to the question are are the equations
y = 0.08x²-1.6x+13
y = 0.08(x-10)²+5
<h3>How to solve for the system of equations</h3>
David starts at (20, 13) and skates along a path that can be modeled by a quadratic function with a vertex at (10, 5).
Vertex form of quadratic function is
y = 
13 = a(x-10)²+5
let x = 20
a(20-10)²+5
13 = 100a + 5
take like terms
13 - 5 = 100a
8 = 100a
divide through by 100
a = 0.08
hence the equation would be
y = 0.08(x-10)²+5
Read more on equations here:
brainly.com/question/9621134
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