Core Logic
Let's expand the terms by grouping real and imaginary parts explicitly:
ω₁ = (8 θ + 7 θ) + i( θ + 4 θ)$$\omega_1 = (8\sin\theta + 7\cos\theta) + i(\sin\theta + 4\cos\theta)$$
ω₂ = ( θ + 4 θ) + i(8 θ + 7 θ)$$\omega_2 = (\sin\theta + 4\cos\theta) + i(8\sin\theta + 7\cos\theta)$$
Notice that if we let u = 8 θ + 7 θ$u = 8\sin\theta + 7\cos\theta$ and v = θ + 4 θ$v = \sin\theta + 4\cos\theta$, then:
ω₁ = u + iv and ω₂ = v + iu$$\omega_1 = u + iv \quad \text{and} \quad \omega_2 = v + iu$$
Step 1: Calculating the Product
Multiplying ω₁$\omega_1$ and \omega_2:
ω₁ω₂ = (u + iv)(v + iu) = uv + iu² + iv² - uv = i(u² + v²)$$\omega_1\omega_2 = (u + iv)(v + iu) = uv + iu^2 + iv^2 - uv = i(u^2 + v^2)$$
Since the product is given as α + iβ$\alpha + i\beta$:
α = 0$\alpha = 0$
β = u² + v² = (8 θ + 7 θ)² + ( θ + 4 θ)²$$\beta = u^2 + v^2 = (8\sin\theta + 7\cos\theta)^2 + (\sin\theta + 4\cos\theta)^2$$
Step 2: Simplifying the expression for alpha + beta
Expanding the terms for β$\beta$:
β = (64 ²θ + 49 ²θ + 112 θ θ) + ( ²θ + 16 ²θ + 8 θ θ)$$\beta = (64\sin^2\theta + 49\cos^2\theta + 112\sin\theta\cos\theta) + (\sin^2\theta + 16\cos^2\theta + 8\sin\theta\cos\theta)$$
α + β = 0 + β = 65 ²θ + 65 ²θ + 120 θ θ$$\alpha + \beta = 0 + \beta = 65\sin^2\theta + 65\cos^2\theta + 120\sin\theta\cos\theta$$
Using the identity ²θ + ²θ = 1$\sin^2\theta + \cos^2\theta = 1$ and 2 θ θ = 2θ$2\sin\theta\cos\theta = \sin 2\theta$:
α + β = 65 + 60 2θ$$\alpha + \beta = 65 + 60\sin 2\theta$$
Step 3: Max and Min Extrema Analysis
Since -1 ≤ 2θ ≤ 1$-1 \le \sin 2\theta \le 1$:
Maximum value p = 65 + 60(1) = 125$$\text{Maximum value } p = 65 + 60(1) = 125$$
Minimum value q = 65 + 60(-1) = 5$$\text{Minimum value } q = 65 + 60(-1) = 5$$
Sum of maximum and minimum bounds equals:
p + q = 125 + 5 = 130$$p + q = 125 + 5 = 130$$
Pattern Recognition
Observe the symmetric structure in complex variables: (u+iv)$(u+iv)$ and (v+iu)$(v+iu)$. Their product structurally completely cancels out the real component, saving you from a highly messy component expansion.
Chapter Mix
Class 11 Mathematics: Complex Numbers
Class 11 Mathematics: Trigonometric Functions