If ab > - 1, bc > - 1 and ca > - 1, then is
- 1
cot-1abc
0
If the function fx = x2 - k + 2x + 2kx - 2 for x ≠ 22 for x = 2 is continuous at x = 2, then k is equal to
- 12
12
If xexy + ye- xy = sin2x, then dydx at x = 0 is
2y2 - 1
2y
y2 - y
y2 - 1
If y = tan-12x - 11 + x - x2, then dydx at x = 1 is equal to
23
1
32
If f(x) = cos-12cosx + 3sinx13, then [f'(x)]2 is equal to
1 + x
1 + 2x
2
If u = tan-11 - x2 - 1x and v = sin-1x, then dudv is equal to
1 - x2
- x
If y = 11 + x + x2, then dydx is equal to
y2(2 + 2x)
- 1 + 2xy2
1 + 2xy2
- y2(1 + 2x)
If g(x) is the inverse of f(x) and f'(x) = 11 + x3, then g'(x) is equal to
g(x)
1 + g(x)
1 + {g(x)}3
11 + gx3
The equation of the tangent to the curve xa + yb = 1 at the point (x1, y1) is xax1 + yby1 = k. Then, the value of k is
3
B.
Given curve is,
xa + yb = 1 ...iOn differentiating w.r.t. to x, we get1a . 12x + 1b . 12ydydx = 0⇒ dydx = - byax ⇒ dydxx1, y1 = - by1ax1∴ Equation of tangent passing through the point (x1, y1) isy - y1 = - by1ax1x - x1 yby1 - y1by1 = - xax1 + x1ax1⇒ xax1 + yby1 = x1ax1 + y1by1 = x1a + y1b⇒ xax1 + yby1 = 1 ∵ from Eq. (i) ∵ at x1, y1, x1a + y1b = 1But, xax1 + yby1 = k∴ k = 1
The slope of the normal to the curve x = t2 + 3t - 8 and y = 2t2 - 2t - 5 at the point (2, - 1) is
67
- 67
76
- 76