Question

solve :expansion of sinntita

​

Answer 1

We have the following general formulas:

{\sin(n\theta) = \displaystyle \sum_{r=0 \atop 2r+1 \leq n} (-1)^r \binom{n}{2r+1} \cos^{n-2r-1}(\theta) \sin^{2r+1}(\theta)}sin(nθ)=

2r+1≤n

r=0

∑

(−1)

r

(

2r+1

n

)cos

n−2r−1

(θ)sin

2r+1

(θ)