cot^2x 积分-搜答案-搜搜考试网

原式=lim(x->0)e^[cot²xln(cosx)]=e^[lim(x->0)ln(cosx)/tan²x]=e^[lim(x->0)ln(cosx)/x²]=e^

洛必达法则上下求导得答案是1/2再答：把cot2x写成cos2x/sin2x

LIM（趋近与0）(cot^2x-1/x^2)=lim(x^2*cos^2x-sin^2x)/(x^2*sin^2x)=lim[(x^2+1)cos^2x-1]/x^4=lim[(1/2)*(x^2+

2/3

∫cot(3x)dx.

原式=∫cos(3x)/sin（3x）dx=1/3∫1/sin(3x)dsin3x=1/3ln绝对值sin3x+c

1+cosx=1+2(cosx/2)^2-1=2(cosx/2)^21+cosx-------=2(cosx/2)^2/2sin(x/2)*cos(x/2)=cot(x/2)sinx

求(sec x)^2积分,

∫dx*(secx)^2=∫dx/(cosx)^2=∫dx[(sinx)^2+(cosx)^2]/(cosx)^2=∫(sinx)^2/(cosx)^2dx+∫dx=∫sinx(-d(cosx))/(

你想漏了,当t=π/2时tanx是无穷大,倒过来,cotx的值不是0吗?

lim(1+x²)^cot²x=lim(1+x²)^(1/x²)(x²cot²x)=lime^(x²/tan²x)=e

QQ42779066,和我语聊告诉你

左边=(sin²x/cos²x-cos²x/sin²x)/(sin²x-cos²x)=[(sin^4x-cos^4x)/cos²x

sin^2x+cos^2x=1所以左边=tan^2x-cot^2x=sin^2x/cos^2x-cos^2x/sin^2x=(sin^4x-cos^4x)/sin^2xcos^2x=(sin^2x+c

lim（x→0）=(1/x^2-cot^2x)=lim（x→0）=(1/x^2-1/tan²x)=lim(x->0)(tan²x-x²)/x²tan²

1/(1-x)^2积分

解∫1/(1-x)²dx=-∫1/(1-x)²d(1-x)=-∫1/u²du=-(-1/u)+C=1/u+C=1/(1-x)+C

tan^2x+cot^2x=tan^2x+1/tan^2x=[(sinx)^4+(cosx)^4]/(sinxcosx)^2={[(sinx)^2+(cosx)^2]^2-2(sinxcosx)^2}

楼上好像写错了,要细心啊两边取对数,得lny=ln【(tan2x)^cot(x/2)】=cot(x/2)ln（tan2x）两边再分别求导,得y'/y={-[csc（x/2)]^2*ln(tan2x)}

我算了下,你看看行不lim(arcsinx/x)^{[cot(x)]^2}（x→0）=lim[1+（arcsinx-x)/x]^{[cot(x)]^2}（x→0）=lim[1+（arcsinx-x)/

原式=∫[(tanx)^2+4cotx+4(cotx)^4]dx=∫[(secx)^2-1]dx+4∫cotxdx+4∫[(cscx)^2-1]^2dx=tanx-x+4∫d(sinx)/sinx+4

积分x(lnx)^2dx

有分部积分知识可知：∫x(lnx)²dx　　=(1/2)∫(lnx)²d(x²)=x²(lnx)²/2—∫xlnxdx=x²(lnx)