早教吧作业答案频道 -->数学-->
已知sina+sin^2a=1,求3cos^2a+cos^4a-2sina+1
题目详情
已知sina+sin^2a=1,求3cos^2a+cos^4a-2sina+1
▼优质解答
答案和解析
sina+sin²a=1
∴sina=1-sin²a=cos²a
3cos^2a+cos^4a-2sina+1
=3sina+sin²a-2sina+1
=sina+1-cos²a+1
=sina+1-sina+1
=2
∴sina=1-sin²a=cos²a
3cos^2a+cos^4a-2sina+1
=3sina+sin²a-2sina+1
=sina+1-cos²a+1
=sina+1-sina+1
=2
看了 已知sina+sin^2a=...的网友还看了以下:
sin(A+60°)=2sinA怎么化解得到30度 2020-05-04 …
三角函数才开始学,若2sin(兀/2+a)+sin(兀+a)=0,则(2sina-cosa)÷(s 2020-06-05 …
△ABC中∵sin(B+A)=2sin(B+C)∴sinC=2sinA为什么? 2020-06-06 …
sin(A+B)=2sin(B+C)怎么化简成sinC=2sinA 2020-06-06 …
为什么sin(A+B)=2sin(B+C),即sinC=2sinA? 2020-06-06 …
已知ΔABC的内角A.B.C满足sin2A+sin(A-B已知ΔABC的内角A.B.C满足sin2 2020-06-27 …
1.已知cos165º=a,求tan195º?2.已知sin(π+a)=1/2,求sin(2π-a 2020-07-22 …
急已知C:x^2+(y-1/2)^2=r^2与y=sin(x)的图像有唯一交点,且交点的横坐标为a 2020-07-31 …
已知a是第三象限角,f(x)=sin(派-a)cos(2派-a)tan(-派-a)/tan(-派) 2020-08-03 …
已知sin(a+四分之派)=五分之三,a大于二分之派小于等于二分之三派,求sin(2a+...已知s 2020-11-10 …