Tangent of the curve!!

圖片參考：http://imgcld.yimg.com/8/n/HA08156933/o/701204090054113873391410.jpg



Note:
equation of tangent to a curve at (x1, y1) is given by
y - y1 = m(x - x1)
where m = (dy / dx) at (x1, y1)

1.) y=6/x at (3,2)dy/dx = -6/(x^2)dy/dx│(3,2) = -6/9 = -2/3∴At (3,2), slopeof tangent = -2/3∴equation oftangent：(y-2)/(x-3) = -2/33(y-2) = -2(x-3)2x + 3y – 12 = 0 2.) y=12/x^1/2 at (1,12)dy/dx = 12(-1/2)[x^(-3/2)] = -6[x^(-3/2)]dy/dx│(1,12) = -6[1^(-3/2)] = -6∴At (1,12), slopeof tangent = -6∴equation oftangent：(y-12)/(x-1) = -6(y-12) = -6(x-1)6x + y – 18 = 0