Length of a parametric curve

Consider the parametric equation
x=11[cos(theta)+(theta)sin(theta)]
y=11[sin(theta)-(theta)cos(theta)]
]

What is the length of the curve for to 0 to 3pi/4?

The arc length ∫ √((dx/dθ)^2 + (dy/dθ)^2) dθ equals

∫(θ = 0 to 3π/4) √[(11θ cos θ))^2 + (11θ sin θ)^2] dθ
= ∫(θ = 0 to 3π/4) 11θ * √[cos^2(θ) + sin^2(θ)] dθ
= ∫(θ = 0 to 3π/4) 11θ dθ
= 11θ^2/2 {for θ = 0 to 3π/4}
= 99π^2 / 32.

I hope this helps!

99 * pi / 32

I showed you this already.