Photo AI

From a point A due south of a tower, the angle of elevation of the top of the tower T is 23° - HSC - SSCE Mathematics Extension 1 - Question 6 - 2008 - Paper 1

Question icon

Question 6

From-a-point-A-due-south-of-a-tower,-the-angle-of-elevation-of-the-top-of-the-tower-T-is-23°-HSC-SSCE Mathematics Extension 1-Question 6-2008-Paper 1.png

From a point A due south of a tower, the angle of elevation of the top of the tower T is 23°. From another point B, on a bearing of 120° from the tower, the angle of... show full transcript

Worked Solution & Example Answer:From a point A due south of a tower, the angle of elevation of the top of the tower T is 23° - HSC - SSCE Mathematics Extension 1 - Question 6 - 2008 - Paper 1

Step 1

Copy or trace the diagram into your writing booklet, adding the given information to your diagram.

96%

114 rated

Answer

Draw the tower with point A directly south of it, making sure to label the angles and distances accurately. Point B should be connected with angle T's respective elevation of 32° from the bearing of 120°.

Step 2

Hence find the height of the tower.

99%

104 rated

Answer

From point A, we can use the tangent of angle 23° to find the height (h) of the tower:

h=AB×tan(23°) h = AB \times \tan(23°)

Calculate the height using the distance AB (200 m):

h=200×tan(23°)200×0.424584.9extm h = 200 \times \tan(23°) \approx 200 \times 0.4245 \approx 84.9 ext{ m}. Therefore, the height of the tower is approximately 84.9 metres.

Step 3

Use this result to solve sin 3θ + sin 2θ = sin θ for 0 ≤ θ ≤ 2π.

96%

101 rated

Answer

Utilize the equation sin 3θ = 3 sin θ - 4 sin³ θ:

  1. Substitute into the equation, giving: 3sinθ4sin3θ+sin2θsinθ=03 sin θ - 4 sin³ θ + sin 2θ - sin θ = 0
  2. Rearranging yields: 4sin3θ+2sinθ+sin2θ=0-4 sin³ θ + 2 sin θ + sin 2θ = 0
  3. Solve for sin 2θ using the identity sin 2θ = 2 sin θ cos θ: 4sin3θ+2sinθ+2sinθcosθ=0-4 sin³ θ + 2 sin θ + 2 sin θ cos θ = 0
  4. Factor to find zeros and solve for values of θ.

The angles satisfying this equation within the range can be found through numerical methods or further analysis.

Step 4

Use the binomial theorem to expand (1 + x)ᵖ + (1 + x)ᵏ, and hence write down the term of (1 + x)ᵖ + q * x² which is independent of x.

98%

120 rated

Answer

Expanding using the binomial theorem:

(1+x)p+q=k=0p+q(p+qk)xk(1 + x)^{p + q} = \sum_{k=0}^{p + q} {p + q \choose k} x^k

To find the term independent of x, set k = 0. The required term in the combined expansion will be the constant term found in the overall expansion.

Step 5

Given that (1 + x)ᵖ + q * (1 + x)ᵖ = (1 + x)ᵖ * (1 + 1/x), apply the binomial theorem and the result of part (i) to find a simpler expression.

97%

117 rated

Answer

From the earlier part, we know how to expand (1 + x)ᵖ:

  1. Rewrite the new expression: (1+x)p(1+xq)=(1+x)p+qx2(1 + x)^p (1 + x^q) = (1 + x)^p + q * x^2
  2. Apply the binomial expansion to the right side: =(1+x)p+qx2= (1 + x)^p + q * x^2
  3. Combine terms from both expansions and isolate those involving x and independent terms to simplify further.

Join the SSCE students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;