What Are the Implications of Superposition of Two Waves?

[Septim]

Greetings,

I have a question on superposition of two waves and I am pretty new to the topic. I am not contended with my solution and seek your evaluation. Any suggestion, comment is welcome.

Thanks in advance.

Homework Statement

Consider the superposition of two waves x₁ = A₁ cos(ω₁t) and x₂ =
A₂ cos(ω₂t + δ). If ω₁$\cong$ ω₂,
(a) What is the beat frequency?
(b) What is the maximum amplitude?
(c) What is the minimum amplitude?

Homework Equations

Trigonometric identities for Product-to-sum and sum-to-product.

The Attempt at a Solution

Attached to the post in jpeg format.

 

[rude man]

Your work is too hard to read. Writing too light.

Anyway, this is just high school trig, really.