Answer:
we have:
∆BDE is similar to ∆BAC
so their side are proportional :
BD/BD=BE/BC
2/BD=4/(6+4)
BD=2×10/4
BD=5
again
BE/BC=DE/AC
4/10=5/AC
AC=5×10/4
AC=25/2
Now,
<u>AC</u><u>=</u><u>2</u><u>5</u><u>/</u><u>2</u><u> </u><u>or</u><u> </u><u>1</u><u>2</u><u>.</u><u>5</u><u>.</u>
<u>AD</u><u>=</u><u>BA-BD</u><u>=</u><u>5</u><u>-</u><u>2</u><u>=</u><u>3</u><u>.</u>
<u>is</u><u> </u><u>your</u><u> </u><u>answer</u><u>.</u>
Answer:
there you go
Step-by-step explanation:
angle DOB is 60 degree.
The trigonometric identity (cos⁴θ - sin⁴θ)/(1 - tan⁴θ) = cos⁴θ
<h3>
How to solve the trigonometric identity?</h3>
Since (cos⁴θ - sin⁴θ)/(1 - tan⁴θ) = [(cos²θ)² - (sin²θ)²]/[1 - (tan²θ)²]
Using the identity a² - b² = (a + b)(a - b), we have
(cos⁴θ - sin⁴θ)/(1 - tan⁴θ) = [(cos²θ)² - (sin²θ)²]/[1 - (tan²θ)²]
= (cos²θ - sin²θ)(cos²θ + sin²θ)/[(1 - tan²θ)(1 + tan²θ)] =
= (cos²θ - sin²θ) × 1/[(1 - tan²θ)sec²θ] (since (cos²θ + sin²θ) = 1 and 1 + tan²θ = sec²θ)
Also, Using the identity a² - b² = (a + b)(a - b), we have
(cos²θ - sin²θ) × 1/[(1 - tan²θ)sec²θ] = (cosθ - sinθ)(cosθ + sinθ)/[(1 - tanθ)(1 + tanθ)sec²θ]
= (cosθ - sinθ)(cosθ + sinθ)/[(cosθ - sinθ)/cosθ × (cosθ + sinθ)/cosθ × sec²θ]
= (cosθ - sinθ)(cosθ + sinθ)/[(cosθ - sinθ)(cosθ + sinθ)/cos²θ × 1/cos²θ]
= (cosθ - sinθ)(cosθ + sinθ)cos⁴θ/[(cosθ - sinθ)(cosθ + sinθ)]
= 1 × cos⁴θ
= cos⁴θ
So, the trigonometric identity (cos⁴θ - sin⁴θ)/(1 - tan⁴θ) = cos⁴θ
Learn more about trigonometric identities here:
brainly.com/question/27990864
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Answer:
Kevin travels for 2 hours at 60 mph and 3.5 hours at 55 mph
Step-by-step explanation:
Let's say that Kevin spends x hours going 60 mph and y hours going 55 mph. We can say that the sum of the two parts is 5.5, so x+y = 5.5 . Next, he goes 60 miles per hour for the first part of the trip, so for each hour he goes 60 mph, he travels 60 miles. We can then denote 60 * x as the distance traveled during the first part of his trip as he goes 60 mph for x hours. Similarly, 55 * y denotes the distance Kevin travels during the second part of his trip. His total distance is thus 60 * x + 55 * y = 312.5 miles
We have
x + y = 5.5
60 * x + 55 * y = 312.5
One way we can solve this is to solve for y in the first equation and plug that into the second. Subtracting x from both sides in the first equation, we get
y = 5.5 - x
Plugging that into the second equation, we get
60 * x + 55 * (5.5-x) = 312.5
60 * x + 55 * 5.5 - 55x = 312.5
5x +302.5 = 312.5
subtract 302.5 from both sides to isolate the x and its coefficient
5x = 10
divide both sides by 5 to solve for x
x = 2
y = 5.5 - x = 5.5 - 2 = 3.5
Therefore, Kevin travels for 2 hours at 60 mph and 3.5 hours at 55 mph
Find f(-5) by substituting x = -5 in the equation.
Therefore, the answer is f(-5) = 16