Description
Exercise 3.1 [Ste10, p. 205]
- The curve y = |x|/ 2 − x2 is called a bullet-nose curve. Find an equation of the tangent line to this curve at the point (1,1).
- Illustrate part (i) by sketch the curve and the tangent line on the same coordinate system.
Exercise 3.2 [Ste10, p. 208] Use the Chain Rule to prove the following.
- The derivative of an even function is an odd function.
- The derivative of an odd function is an even function.
Exercise 3.3 [Ste10, p. 208] If y = f(u) and u = g(x), where f and g are twice differentiable functions, show that
d
dx2 du2 dx du dx
Exercise 3.4 [Ste10, p. 215] Use implicit differentiation to find an equation of the tangent line to the curve at the given point.
(cardioid).
√
- ) (astroid) x2/3 + y2/3 = 4 at (−3 3,1).
- ( (lemniscate) 2(x2 + y2)2 = 25(x2 − y2) at (3,1).
- ) (devil’s curve) y2(y2 − 4) = x2(x2 − 5) at (0,−2).
Exercise 3.5 [Ste10, Sec. 3.11] Given the following hyperbolic functions defined as
coth
| (i) (3pts) Show that | ||
| d
(sinhx) = coshx |
d
(coshx) = sinhx |
d 2
(tanhx) = sech x |
dx dx dx
| (cschx) = cschxcothx
dx (ii) (3pts) and show that1 |
(sechx) = sechxtanhx
dx |
(cothx) = csch x
dx |
d d d 2 −−−
d −1 1
(tanh x) =
dx 1 − x2 d −1 1
dx 1 − x2
1Notice that the formulas for the derivatives of tanh−1x and coth−1x appear to be identical. But the domains of these functions have no numbers in common: tanh−1x is defined for |x| < 1, whereas coth−1x is defined for |x| > 1.
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Exercise 3.6 [Ste10, p. 223] Find the derivative of the following functions (i) (1pt) y = (sinx)lnx
(ii) (1pt) y = (tanx)1/x
Exercise 3.7 [Ste10, p. 272] If
Show that.
Exercise 3.8 [Ste10, p. 282] If f has a local minimum value at c, show that the function g(x) = −f(x) has a local maximum value at c.
Exercise 3.9 [Ste10, p. 289] Suppose f is an odd function and is differentiable everywhere. Show that for every positive number b, there exists a number c ∈ (−b,b) such that f′(c) = f(b)/b.
Exercise 3.10 [Ste10, p. 300] Show that the inflection points of the curve y = xsinx lie on the curve y[1](x2+4) = 4x2.
Exercise 3.11 [Ste10, p. 309] Evaluate
Exercise 3.12 [Ste10, p. 309] Let
- Show that f is continuous at 0.
- Calculate f′(0).
Exercise 3.13 [Ste10, p. 309] Show that the shortest distance from the point (x1,y1) to the straight line Ax + By + C = 0




