The trigonometric identity (cos⁴θ - sin⁴θ)/(1 - tan⁴θ) = cos⁴θ
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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:
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Answer:
When x = 2, y = 6
Step-by-step explanation:
Constant of Proportionality: y = kx
(24) = k(8)
24 = 8k
k = 3
y = kx ===> y = 3x
When x = 2:
y = 3x
y = 3(2)
y = 6
-8 and 7.
Use the quadratic formula or factor and set equal to 0.
Answer:
43.13 yd squared
Step-by-step explanation:
This is a figure composed of a semicircle and a right triangle.
Triangle:
The area of a triangle is denoted by A = (1/2) * B * h, where b is the base and h is the height. Here, the base is actually also the radius of the semicircle, which is 4. The height is 9. Plug these in: A = (1/2) * 4 * 9 = 36/2 = 18 yd squared.
Semicircle:
The area of a semicircle is denoted by A = , where r is the radius. Here the radius is 4. So: A = ≈ 25.13 yd squared.
Adding these up: 18 + 25.13 = 43.13 yd squared
Hope this helps!