A. $\int_{\alpha}^{\beta} f(\varphi(t), \psi(t))\, dt$
B. $\int_{\beta}^{\alpha} f(\varphi(t), \psi(t))\sqrt{\varphi'^2(t)+ \psi'^2(t)} \, dt$
C. $\int_{\alpha}^{\beta} f(\varphi(t), \psi(t))\sqrt{\varphi'^2(t)+ \psi'^2(t)} \, dt$
D. $\int_{\beta}^{\alpha} f(\varphi(t), \psi(t))\, dt$
设 l: {x=varphi(t) y=psi(t) [P(varphi(t), psi(t))+ Q(varphi(t), psi(t))] psi(t),
设函数 varphi(x) 连续，且满足 varphi(x)= e^x + int_0^x t varphi(t), dt - x int_0^x varphi
设f(x)连续, varphi (x)=(int )_(0)^1f(xt)dt, 且 lim _(xarrow 0)dfrac (f(x))(x)=A设f(x)
已知 f(x) 的参数方程为 } x = cos t y = sin t ，则参数 t = (pi)/(4) 处切线方程为( )A. $x + y - \sq
5.(单选题) 设 z = varphi(x + y) + psi(x - y), 则必有()A. $z_{xx}^{\prime\prime} + z_{yy
6.设函数φ(x)连续，且满足varphi(x)=e^x+int_(0)^xtvarphi(t)dt-xint_(0)^xvarphi(t)dt,求φ(x).6
5.已知f(x)二阶可导，且f(x)≠0，varphi(x)=lim_(tto0)((f(x+t))/(f(x)))^(1)/(sin t)，则varphi^p
5.已知f(x)二阶可导，且f(x)≠0，varphi(x)=lim_(tto0)((f(x+t))/(f(x)))^(1)/(sin t)，则varphi^p
【题目】12、设函数f(x)在 [0,1] 上连续,且 f(x)0F(x)=∫_0^xf(t)dt+∫_1^x1/(f(t))dt, x∈[0,1]证明:方程F
12.设函数f(x)连续，且满足f(x)=e^x+int_(0)^xtf(t)dt-xint_(0)^xf(t)dt，求f(x).12.设函数f(x)连续，且满