Express $\cos^5t$ in terms of $\cos 5t,\cos3t,\cos t$ and express $\sin^4t$ in terms of $\cos 4t, \cos 2t$

• Other examples like this one are contained in the Algebra Notes Ch3 page 98 Example 3 and 4 ! Please also read this book, as it has many useful examples!!
• RTB - Read the Book 😎