![If \\( \\cos 5 \\theta = a \\cos \\theta + b \\cos ^ { 3 } \\theta + c \\cos ^ { 5 } \\theta + d \\) , then\n\\( \\begin{array} { l l l l } { \\text { a. } a = 20 } & { \\text { b. } b = - 20 } & { \\text { c. } c = 16 } \\end{array} \\)\" If \\( \\cos 5 \\theta = a \\cos \\theta + b \\cos ^ { 3 } \\theta + c \\cos ^ { 5 } \\theta + d \\) , then\n\\( \\begin{array} { l l l l } { \\text { a. } a = 20 } & { \\text { b. } b = - 20 } & { \\text { c. } c = 16 } \\end{array} \\)\"](https://d2rrqu68q7r435.cloudfront.net/images/9602233/a3ecffe9-ced9-49c1-9226-c7f0fa8a1e7d.jpg)
If \\( \\cos 5 \\theta = a \\cos \\theta + b \\cos ^ { 3 } \\theta + c \\cos ^ { 5 } \\theta + d \\) , then\n\\( \\begin{array} { l l l l } { \\text { a. } a = 20 } & { \\text { b. } b = - 20 } & { \\text { c. } c = 16 } \\end{array} \\)\"
![to prove cos pi 5 cos 2 pi 5 cos 4 pi 5 cos 8 pi 5 1 16 please answer soon - Mathematics - TopperLearning.com | jhw7xbb to prove cos pi 5 cos 2 pi 5 cos 4 pi 5 cos 8 pi 5 1 16 please answer soon - Mathematics - TopperLearning.com | jhw7xbb](https://images.topperlearning.com/topper/tinymce/integration/showimage.php?formula=a395c02c365cc4e4c3e25c81d87fe353.png&d=0)
to prove cos pi 5 cos 2 pi 5 cos 4 pi 5 cos 8 pi 5 1 16 please answer soon - Mathematics - TopperLearning.com | jhw7xbb
![If $\cos (α + β) = 4 / 5$ and $\sin (α – β) = 5 / 13$, where $α$ lie between $0$ and $\pi/4$, find the value of $\tan2α$. - Mathematics Stack Exchange If $\cos (α + β) = 4 / 5$ and $\sin (α – β) = 5 / 13$, where $α$ lie between $0$ and $\pi/4$, find the value of $\tan2α$. - Mathematics Stack Exchange](https://i.stack.imgur.com/a8BWP.jpg)