第1个回答 2013-04-07
因为该图像函数y =(x)的=π/ 4对称
(1)(-π/ 2)=(π)= 0时,f(-π/ 4)= (3π/ 4),√2/2
(2)当-π/ 2 <= X <=π/ 4时,f(x)的=(π/2-x)
圆周率/ 4 =π/2-x<=圆周率,F(x)的= F(π/2-x)= SIN(π/2-x)= cosx
所以当 - π/ 2 <= x <=π/ 4时,f(x)的= cosx的
当PI / 4 = <X <=圆周率,当函数f(x)= sinx的
第2个回答 2013-04-07
7. 选B
sinθcosθ=1/2
tanθ+cosθ/sinθ = (sin²θ+cos²θ)/(sinθcosθ)
= 2
第3个回答 2013-04-07
因为tanx=sinx/cosx则tanx+cosx/sinx=sinx/cosx+cosx/sinx=(sinx^2+cosx^2)/sinxcosx
因为sinx^2+cosx^2=1,sinxcosx=1/2则原式=2故应选择答案B
第4个回答 2013-04-07
答案应该是这样的。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/55e736d12f2eb93836a09a97d4628535e4dd6f82?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)