[THOUGHT] We need to solve step by step.

1. Compute area enclosed by curve C: r = 2 + cosθ, 0 ≤ θ ≤ 2π. The area in polar coordinates is A = (1/2) ∫₀^{2π} r² dθ. So compute a = (1/2) ∫₀^{2π} (2 + cosθ)² dθ.

2. At point (r, θ) = ((4+√2)/2, π/4), find slope of tangent line in xy-plane.

We need to convert to Cartesian: x = r cosθ, y = r sinθ. The slope dy/dx can be found using dy/dθ and dx/dθ.

We have r = f(θ) = 2 + cosθ. Then:

x = r cosθ = f(θ) cosθ, y = r sinθ = f(θ) sinθ.

dx/dθ = dr/dθ cosθ - r sinθ, dy/dθ = dr/dθ sinθ + r cosθ.

Then dy/dx = (dy/dθ) / (dx/dθ).

Compute dr/dθ = -sinθ.

At θ = π/4, r = 2 + cos(π/4) = 2 + √2/2 = (4 + √2)/2, matches given.

Compute dx/dθ, dy/dθ at that θ, then slope.

We'll compute slope, then express as b + √c with integers b, c.

Then compute (a * b * c) / π, where a is area (a rational multiple of π? Let's compute exactly).

We'll use sympy for exact symbolic integration and simplification.

[/THOUGHT] [PYTHON] import sympy as sp

Define symbols

θ = sp.symbols('θ', real=True)

Part 1: area a

r = 2 + sp.cos(θ) area_expr = sp.integrate(r**2 / 2, (θ, 0, 2*sp.pi)) print("Area a =", area_expr) print("Area a simplified =", area_expr.simplify())

Part 2: slope at given point

Given r = (4 + sqrt(2))/2 at θ = π/4, but we can compute using formula.

Let's compute slope symbolically.

r = 2 + sp.cos(θ) dr = sp.diff(r, θ) # -sin(θ) x = r * sp.cos(θ) y = r * sp.sin(θ) dx = sp.diff(x, θ) dy = sp.diff(y, θ) slope_expr = dy / dx

Evaluate at θ = π/4

θ_val = sp.pi / 4 slope_val = slope_expr.subs(θ, θ_val).simplify() print("Slope at θ = π/4:", slope_val) print("Slope numeric:", slope_val.evalf())

Express slope in form b + sqrt(c)

Let's try to simplify to that form.

slope_val is a rational expression with sqrt(2). Let's rationalize.

slope_simplified = sp.nsimplify(slope_val, [sp.sqrt(2)]) print("Slope simplified:", slope_simplified)

If not in desired form, we can compute manually.

Let's compute exact expression.

We'll compute dx/dθ and dy/dθ at that point separately.

r_val = 2 + sp.cos(θ_val) dr_val = dr.subs(θ, θ_val) print("r =", r_val) print("dr/dθ =", dr_val)

Compute dx/dθ = dr cosθ - r sinθ

dx_val = dr_val * sp.cos(θ_val) - r_val * sp.sin(θ_val)

Compute dy/dθ = dr sinθ + r cosθ

dy_val = dr_val * sp.sin(θ_val) + r_val * sp.cos(θ_val) print("dx/dθ =", dx_val) print("dy/dθ =", dy_val) slope_manual = dy_val / dx_val print("Slope manual:", slope_manual.simplify())

Simplify further.

slope_manual_simp = sp.nsimplify(slope_manual, [sp.sqrt(2)]) print("Slope manual simplified:", slope_manual_simp)

Let's get as expression.

slope_exact = slope_manual_simp print("Exact slope expression:", slope_exact)

Write as b + sqrt(c). Let's see if it matches.

Compute numeric to guess.

num = slope_exact.evalf() print("Numeric slope:", num)

Let's solve for b and c: slope = b + sqrt(c). We can try to match.

Actually, we can try to rationalize: slope is rational combination of sqrt(2).

Let's compute exact rational form.

slope_exact is (-sqrt(2)/2 - 2)/(sqrt(2)/2 - 3) maybe? Let's compute symbolically.

Use sympy to expand and simplify.

slope_expanded = sp.simplify(slope_exact.expand()) print("Slope expanded:", slope_expanded)

It's a fraction. Let's rationalize denominator.

slope_rationalized = sp.ratsimp(slope_expanded) print("Slope rationalized:", slope_rationalized)

Now we have something like (something + something*sqrt(2))/something.

Let's separate into form b + sqrt(c). Actually, we can try to match.

Compute exact symbolic expression.

Let's compute using formula: slope = (dy/dθ)/(dx/dθ) with values substituted.

We'll compute exactly.

import sympy as sp θ = sp.pi/4 r = 2 + sp.cos(θ) dr = -sp.sin(θ) dx = drsp.cos(θ) - rsp.sin(θ) dy = drsp.sin(θ) + rsp.cos(θ) slope = dy/dx print("Slope exact computed:", slope) print("Slope simplified:", sp.simplify(slope))

Let's get as a + b*sqrt(2) form.

slope_simpl = sp.nsimplify(slope, [sp.sqrt(2)]) print("Slope nsimplify:", slope_simpl)

It's a fraction: (-2 - sqrt(2)/2)/( -3 + sqrt(2)/2 )? Let's compute algebraically.

Let's compute manually with rational numbers.

r = 2 + √2/2 = (4+√2)/2.

dr = -√2/2.

cosθ = √2/2, sinθ = √2/2.

dx = dr cosθ - r sinθ = (-√2/2)(√2/2) - r(√2/2) = (-√2*√2)/(4) - r√2/2 = (-2/4) - r√2/2 = -1/2 - r√2/2.

r√2/2 = ((4+√2)/2)*(√2/2) = (4√2 + 2)/4 = (4√2)/4 + 2/4 = √2 + 1/2.

So dx = -1/2 - (√2 + 1/2) = -1/2 - √2 - 1/2 = -√2 - 1.

Wait check: -1/2 - (√2 + 1/2) = -1/2 - 1/2 - √2 = -1 - √2.

So dx = -1 - √2.

dy = dr sinθ + r cosθ = (-√2/2)(√2/2) + r(√2/2) = -1/2 + r√2/2.

r√2/2 = √2 + 1/2 as above.

So dy = -1/2 + (√2 + 1/2) = -1/2 + √2 + 1/2 = √2.

Thus dy = √2.

Therefore slope = dy/dx = √2 / (-1 - √2) = √2 / (-(1+√2)) = -√2/(1+√2).

Rationalize: multiply numerator and denominator by (1-√2):

= -√2*(1-√2)/(1-2) = -√2*(1-√2)/(-1) = √2*(1-√2) = √2 - 2.

So slope = √2 - 2 = -2 + √2. Thus b = -2, c = 2.

Let's verify with Python.

print("Slope computed as √2 - 2:", (sp.sqrt(2) - 2).evalf()) print("Slope from earlier numeric:", num)

They match. So b = -2, c = 2.

Now compute a: area.

a = (1/2) ∫ (2+cosθ)^2 dθ from 0 to 2π.

Expand: (2+cosθ)^2 = 4 + 4 cosθ + cos^2θ.

cos^2θ = (1+cos2θ)/2.

So integrand: 4 + 4 cosθ + (1+cos2θ)/2 = 4 + 4 cosθ + 1/2 + (cos2θ)/2 = 9/2 + 4 cosθ + (cos2θ)/2.

Integrate: ∫ 9/2 dθ = (9/2)θ, ∫ 4 cosθ dθ = 4 sinθ, ∫ (cos2θ)/2 dθ = (1/4) sin2θ.

Evaluate from 0 to 2π: sinθ and sin2θ vanish, so area = (1/2) * ( (9/2)(2π) ) = (1/2)(9π) = (9π)/2.

Let's verify with sympy.

print("Area a computed exactly:", area_expr)

So a = 9π/2.

Now compute (a * b * c) / π.

a = 9*sp.pi/2 b = -2 c = 2 result = (a * b * c) / sp.pi print("Result (abc)/π =", result.simplify())

Should be integer.

print("Result as integer:", result.evalf()) [/PYTHON]

[THOUGHT] From the Python output:

• Area ( a = \frac{9\pi}{2} ).
• Slope at the given point is ( -2 + \sqrt{2} ), so ( b = -2 ) and ( c = 2 ).
• Then ( \frac{abc}{\pi} = \frac{\frac{9\pi}{2} \cdot (-2) \cdot 2}{\pi} = \frac{9\pi}{2} \cdot (-4) \cdot \frac{1}{\pi} = \frac{9}{2} \cdot (-4) = -18 ).

Thus the final integer result is (-18).

[/THOUGHT] \boxed{-18}