tana=2 则2sin^2+3cos^2a等于多少tana=2 则2sin^2a+3cos^2a等于多少

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tana=2 则2sin^2+3cos^2a等于多少tana=2 则2sin^2a+3cos^2a等于多少
tana=2 则2sin^2+3cos^2a等于多少
tana=2 则2sin^2a+3cos^2a等于多少

tana=2 则2sin^2+3cos^2a等于多少tana=2 则2sin^2a+3cos^2a等于多少
2sin^2a+3cos^2a
=(2sin^2a+3cos^2a)/1
=(2sin^2a+3cos^2a)/(sin^2a+cos^2a) 分子分母同时除以cos^2a
=(2tan^2a+3)/(tan^2a+1) tana=2
=(8+3)/(4+1)
=11/5

2sin^2a+3cos^2a
=(2sin^2a+3cos^2a)/1
=(2sin^2a+3cos^2a)/(sin^2a+cos^2a) (上下同除以cos^2a)
=(2tan^2a+3)/(tan^2a+1)
=11/5

若tana=1/3,则sin^3 a+2cos^ 3 a/sin^3 a-2cos^3 a tana=2,则sin(a+3兀)+cos(兀+a)/sin(-a)-cos(兀+a)= tana=2 则2sin^2+3cos^2a等于多少tana=2 则2sin^2a+3cos^2a等于多少证明cos^4 a-sin^4 a=cos^2(1-tana)(1+tana) 证明sin^4 a+cos^4 a=cos^2(1-tana)(1+tana) 已知tana=2,则2sin^2a-3sinacosa+cos^2a=? 已知tana=2,则2/3(sin*2)a+1/4(cos*2)a=? sin^2a+2sinacosa-3cos^2a= -3,则tana的值? 已知tana=2 则2sin²a-3sinacosa-2cos²a=? 已知tana=2 则sin^2a +sinacosa+3cos^2a的值若tana=-2则sin^2a-3cos^2a的值为多少已知tana=3,则sin^2a-3sinacosa+cos^2a的值是? 已知tana=3,则sin^2a-cos^2a= 若tana=√3 ,则cos2a-cos^2 a / sin^2 a-1= 已知tana=3,则sin^2 a-cos^ 2 a=? 已知tana=3,则sin^2a-4sinacosa+4cos^2a+1= 已知tana=2,则sina/sin^3a-cos^3a= 已知tanA=2,则sin²A- 3cos²A=?