當(dāng)x = 0,∫(1~y) e^-t² dt = 0 => y = 1
x - ∫(1~x+y) e^-t² dt = 0
e^[-(x+y)²] * (1 + y') = 1
1 + y' = e^(x+y)²
y' = e^(x+y)² - 1
y'|_x=0,y=1) = e^(0+1)² - 1 = e - 1
切線方程為y - 1 = (e - 1)(x - 0)
即(e - 1)x - y + 1 = 0