sin³x-cos³x cosx-sinx
来源:学生作业帮助网 编辑:作业帮 时间:2024/09/30 01:36:34
sin(-x)=sin(x),cos(-x)=-cosx对吗?不对,反了应sin(-x)=-sin(x),cos(-x)=cosx
(1)设√X=t,x=t^2,dx=dt^2=2tdt∫cos√Xdx=∫cost×2tdt分部积分:原式=2∫tdsint=2t×sint-2∫sintdt=2t×sint+2cost=2√Xsin
y=sin^2x+√3sin^2xcosx+2cos^2x你确定那边+√3sin^2xcosx如果是+√3sinxcosx那么y=sin^2x+√3sinxcosx+2cos^2x=1/2(2cos^
利用换元法与分部积分法求不定积分∫(xcosx/sin³x)dx求高手破解∫(xcosx/sin³x)dx=-(1/2)∫[xd(1/sin²x)]=-(1/2)[x/s
f(x)=sin³xcosx+cos³xsinx+√3sin²x=sinxcosx(sin²x+cos²x)+√3(1-cos2x)/2=½
∫[xcosx/(sinx)^2]dx=∫[x/(sinx)^2]d(sinx)=-∫xd(1/sinx)=-x/sinx+∫(1/sinx)dx=-x/sinx+∫[sinx/(sinx)^2]dx
sin^2x+cos^2x=1
这个方程无解取区间[-π,π]-1
Y=cos^4x-2sinxcosx-sin^4x=cos^4x-sin^4x-2sinxcosx=(cos^2x-sin^2x)*1-sin2x=cos2x-sin2x=根号2倍的cos(x+4分之
=sin^2(x)*[cos^2(x)-1]=-sin^4(x)再答:别忘了负号再问:嗯谢谢
有公式sin(a+b)=sinacosb+cosasinb所以sin(x+π/3)=sinxcosπ/3+cosxsinπ/3=1/2sinx+√3/2cosx
∫cos2xdx/(sin^2xcos^2x)=4∫cos2xdx/(2sinxcosx)^2=4∫cos2xdx/(sin2x)^2=2∫cos2xd(2x)/(sin2x)^2=2∫d(sin2x
2cosx(sinx-cosx)+1=2sinxcosx-2cosx^2+1=sin2x+1-2cosx^2=sin2x-cos2x=√2sin(2x-π/4)
该函数在x=0处的左右极限都没有比如x=1/(2npi+pi/2)时,f(x)=1x=1/(2npi-pi/2)时,f(x)=-1取n->无穷大所以在x=0处没有右极限,左极限同理
tanx=-1/2sinx/cosx=-1/2cosx=-2sinx代入:sin²x+cos²x=15sin²x=1sin²x=1/5sin²x+3s
sinx=2cosx,sin^2x=4cos^2xsin^2x=4-4sin^2x,sin^2x=4/5(cosx+sinx)/(cosx-sinx)+sin^2x=(1+tanx)/(1-tanx)
(x*sinx*cosx)'=(1/2xsin2x)'=1/2(sin2x+xcos2x*2)=1/2sin2x+xcos2x
利用积化和差公式sinAcosB=(1/2)*[sin(A+B)+sin(A-B)]以及sin(-A)=-sinA的性质可得sin(x)(cos(x)+cos(3x)+cos(5x)+cos(7x))