By definition of tangent,
tan(2<em>θ</em>) = sin(2<em>θ</em>) / cos(2<em>θ</em>)
Recall the double angle identities:
sin(2<em>θ</em>) = 2 sin(<em>θ</em>) cos(<em>θ</em>)
cos(2<em>θ</em>) = cos²(<em>θ</em>) - sin²(<em>θ</em>) = 2 cos²(<em>θ</em>) - 1
where the latter equality follows from the Pythagorean identity, cos²(<em>θ</em>) + sin²(<em>θ</em>) = 1. From this identity we can solve for the unknown value of sin(<em>θ</em>):
sin(<em>θ</em>) = ± √(1 - cos²(<em>θ</em>))
and the sign of sin(<em>θ</em>) is determined by the quadrant in which the angle terminates.
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We're given that <em>θ</em> belongs to the third quadrant, for which both sin(<em>θ</em>) and cos(<em>θ</em>) are negative. So if cos(<em>θ</em>) = -4/5, we get
sin(<em>θ</em>) = - √(1 - (-4/5)²) = -3/5
Then
tan(2<em>θ</em>) = sin(2<em>θ</em>) / cos(2<em>θ</em>)
tan(2<em>θ</em>) = (2 sin(<em>θ</em>) cos(<em>θ</em>)) / (2 cos²(<em>θ</em>) - 1)
tan(2<em>θ</em>) = (2 (-3/5) (-4/5)) / (2 (-4/5)² - 1)
tan(2<em>θ</em>) = 24/7
Answer:
<h3>4.c</h3><h3>5.a</h3>
Step-by-step explanation:
<h3>#CARRY ON LEARNING</h3><h3>#MARK BRAINLITS</h3>
Answer:
See below.
Step-by-step explanation:
The domain which is all the posible values of x is: x is real and in the interval
[1, 6].
The range is real f(x) in the interval [1, 7].
Answer:
6) -7 + 10 = 3 (3 more; total number doesn't matter)
7) 50w + 20
8) c / 5
9) 5 + 2t
10) 4d + 2d
I didn't see the trick problem!
Answer:
The solution is the point (0.5,-3)
Step-by-step explanation:
we have
----> equation A
----> equation B
Solve the system by substitution
Substitute equation B in equation A
Solve for x
Adds 5 both sides
Divide by 4 both sides
therefore
The solution is the point (0.5,-3)
<em>Verify your answer using the graph</em>
using a graphing tool
Remember that the solution of the system of equations is the intersection point both graphs
The intersection point is (0.5,-3)
therefore
The solution is the point (0.5,-3)
see the attached figure
