高一三角函数 化简求值[sin(7π/2+a)*cos(a-π)*sin^2 (a+2π)]/[cos(3/2+π)*tan(π+a)*cos^3(-a-π)]
问题描述:
高一三角函数 化简求值
[sin(7π/2+a)*cos(a-π)*sin^2 (a+2π)]/[cos(3/2+π)*tan(π+a)*cos^3(-a-π)]
答
[sin(7π/2+a)*cos(a-π)*sin^2 (a+2π)]/[cos(3π/2+a)*tan(π+a)*cos^3(-a-π)]
=[-cosa*(-cosa)*sin^2a]/[sina*tana*(-cos^3a)]
=cos^2asin^2a/sin^2a(-cos^2a)
=-1