已知tanx=2，则1+2sin2x=（ ）
A: 53
B: 73
C: 94
D: 135
A: 53
B: 73
C: 94
D: 135
举一反三
- 1、已知cos4α=2/3,则(sin^4α-cos^4α)^2=2、(1-cosx+sinx)/(1+cosx+sinx)=-2,则tanx=
- 已知 \( y = \sin x + \ln 2 \)，则 \( y' = \cos x + {1 \over 2} \)（ ）.
- 设\(z = \int_ { { x^2}}^y { { e^t}\sin t} dt\)，则\({z_{xx}=}\) A: \(2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} + 2{x^2}\cos {x^2}} \right]\) B: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} - 2{x^2}\cos {x^2}} \right]\) C: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} + 2{x^2}\cos {x^2}} \right]\) D: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\cos {x^2} + 2{x^2}\sin {x^2}} \right]\)
- 17e0b849d3a4a3b.jpg,计算[img=19x34]17e0ab14a855463.jpg[/img]的实验命令为（ ）. A: syms x; f=diff((1+sin(x)^2)/cos(x),1)f=2*sin(x) + (sin(x)*(sin(x)^2 + 1))/cos(x)^2 B: f=diff((1+sinx^2)/cosx,1)f=1/2/x^(1/2)/(1-x)^(1/2) C: syms x;f=diff((1+sinx^2)/cosx,1)f=2*sin(x) + (sin(x)*(sin(x)^2 + 1))/cos(x)^2
- 计算 [img=61x41]17da60e4003aded.png[/img]实验命令为(). A: syms x; limit(tan(x)/(2*x))ans =1/2 B: syms x; limit(tanx/(2*x))ans =1/2 C: limit(tanx/(2*x),x,0)ans =1/2