You're given that φ is an angle that terminates in the third quadrant (III). This means that both cos(φ) and sin(φ), and thus sec(φ) and csc(φ), are negative.
Recall the Pythagorean identity,
cos²(φ) + sin²(φ) = 1
Multiply the equation uniformly by 1/cos²(φ),
cos²(φ)/cos²(φ) + sin²(φ)/cos²(φ) = 1/cos²(φ)
1 + tan²(φ) = sec²(φ)
Solve for sec(φ) :
sec(φ) = - √(1 + tan²(φ))
Given that cot(φ) = 1/4, we have tan(φ) = 1/cot(φ) = 1/(1/4) = 4. Then
sec(φ) = - √(1 + 4²) = -√17
1) The ratio of used books to all books is 6:14
2) The ratio of used books to new books is 6:8
Answer:
x = 3 and x = -7
Step-by-step explanation:
The given quadratic equation is
. We need to find the solution of this equation.
If the equation is in the form of
, then its solutions are given by :

Here, a = 1, b = 4 and c = -21
Plugging all the values in the value of x, such that :

So, the solutions of the quadratic equation are 3 and -7.
Answer:
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