计算sin(π/10)x sin (13π/10)

计算sin(π/10)x sin (13π/10) sin（x+a)*sin(x-a)应如何计算 sin(x+π/4) 计算,sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8) sin兀x的周期怎么计算 计算∫sin(lnx)/x dx sin x sin^2(π/3-x)+sin^2(π/6+x) 2sin(x+π/4)sin(x-π/4)=? sin(x+π/4)sin(x-π/4)等于什么? sinπ(x-1)=-sinπx如何证明 sin(sin(x))的奇偶性 sin x + sin πx 的周期是多少? 计算:sin方10°+sin方20°+sin方30°+sin方40°+sin方50°+sin方60°+sin方70°+sin方80°+sin方90°= sin^2(π/4 +x) sinπx的导数 sin(πx/2)求导 -sin(π+x)等于多少?