A right triangle has two acute angles, θ and ϕ, so that cosϕ=x+0.2 and sinθ=2x−0.5. What is the value of x? (1 point)

0.7

10

1

0.07

1 answer

To solve for x, we can use the identities of a right triangle:

cos^2(θ) + sin^2(θ) = 1

Given that sinθ = 2x - 0.5, we can square both sides:

(sinθ)^2 = (2x - 0.5)^2

And given that cosϕ = x + 0.2, we can square both sides:

(cosϕ)^2 = (x + 0.2)^2

Now we can substitute these squared values into the first identity:

(sinθ)^2 + (cosϕ)^2 = 1

(2x - 0.5)^2 + (x + 0.2)^2 = 1

Expand and simplify the equation:

4x^2 - 2x + 0.25 + x^2 + 0.4x + 0.04 = 1

Combine like terms:

5x^2 + 0.4x - 0.71 = 1

Rearrange the equation:

5x^2 + 0.4x - 1.71 = 0

Now we can solve this quadratic equation. Using the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / (2a)

a = 5, b = 0.4, c = -1.71

x = (-0.4 ± √(0.4^2 - 4*5*-1.71)) / (2*5)

x = (-0.4 ± √(0.16 + 34.2)) / 10

x = (-0.4 ± √34.36) / 10

x ≈ (-0.4 ± 5.86) / 10

x ≈ 5.46 / 10 or x ≈ (-6.26) / 10

x ≈ 0.546 or x ≈ -0.626

Since x represents a length, it cannot be negative.

Therefore, the value of x is approximately 0.546.

Answer: 0.546