Inverse Trigonometric Derivatives Review. Find The Derivativ ✓ Solved
Inverse trigonometric derivatives review. Find the derivative
1. Find the derivative of the following functions:
- d/dx (ln(tan-1(x2 + 3))). For what values of x is this derivative valid?
- d/dx (π sec-1(x2 - 1)). For what values of x is this derivative valid?
- d/dx (11 sin-1(-3x)). For what values of x is this derivative valid?
2. Consider the linear function y = 1 - 2x. Find the inverse function, then compute the derivatives of both functions. What do you notice?
3. If f is differentiable at a point x0, then the derivative of f-1 at an appropriate point should be 1/f'(x0), if f'(x0) ≠ 0:
- (a) Sketch the graph of y = √(x - 1), then find and carefully sketch its inverse on the same graph.
- (b) Find the tangent line to the graph of y = √(x - 1) at the point where x = 5. Sketch the tangent line on your curve.
- (c) What is the corresponding tangent line on the graph of the inverse function? What is its slope?
- (d) Compute the derivative of the inverse function directly. What input value must you plug in to get 1/y'(5)?
4. If f is differentiable and has an inverse on some interval I, then f-1 is differentiable at y0 = f(x0), and (f-1)'(y0) = 1/f'(x0). Use this to determine (f-1)'(3) for the function f(x) = x3 + x + 1, without finding the inverse first.
Paper For Above Instructions
In this assignment, we will explore the derivatives of various functions, including inverse trigonometric functions, linear functions, and their inverses, while also discussing geometric insights into derivatives and their relationships.
1. Derivatives of Inverse Trigonometric Functions
(a) To find the derivative of the function ln(tan-1(x2 + 3)), we will apply the chain rule. The derivative is given by:
D = d/dx [ln(tan-1(x2 + 3))] = 1/(tan-1(x2 + 3)) * d/dx[tan-1(x2 + 3)].
The derivative of tan-1(u) with respect to u is 1/(1 + u2), and hence:
Basically, we let u = x2 + 3, giving us: d/dx[tan-1(u)] = 1/(1 + (x2 + 3)2) * 2x.
Combining these results, we have:
D = 2x / ((1 + (x2 + 3)2)(tan-1(x2 + 3))).
Finding the values of x for which this derivative is valid involves ensuring tan-1(x2 + 3) is defined. This holds for all real x, yielding no restrictions from the logarithmic or the inverse tangent function.
(b) For the function π sec-1(x2 - 1), we utilize the following derivatives:
D = d/dx [π sec-1(v)] = π * d/dx [sec-1(v)] where v = x2 - 1.
We know the derivative of sec-1(u) is 1 / (|u|√(u2 - 1)): Thus, we derive:
D = π * 2x / (|x2 - 1|√((x2 - 1)2 - 1)) where x must not be ±1 for validity.
(c) For the function 11 sin-1(-3x), we use the chain rule:
D = 11 (1 / √(1 - (-3x)2)) (-3) = -33 / √(1 - 9x2).
This expression is valid for -1/3
2. Finding the Inverse of a Linear Function
Let us now examine the linear function y = 1 - 2x. The inverse can be derived by swapping x and y:
y = 1 - 2x -> 2x = 1 - y -> x = (1 - y)/2.
Thus, the inverse function is f-1(y) = (1 - y)/2.
Now computing the derivatives, we get:
f'(x) = -2 and f-1'(y) = -1/2. Notice that the product of the slopes yields -1, confirming that the derivatives of inverse functions are negative reciprocals in linear cases.
3. Exploring Geometry of Inverse Functions
(a) For the function y = √(x - 1), the graph can be sketched along with its inverse formed by reflecting it over the line y = x.
(b) The tangent at x = 5 can be evaluated: y = √(4) = 2. Slope: y' = 1/(2√(x - 1)) = 1/4. The tangent equation is y - 2 = (1/4)(x - 5).
(c) Examining the inverse function's tangent slope will yield a slope of 4.
(d) To find 1/y'(5): input = 1/nav(y') = 4 for which you must plug in a value around this point.
4. Application of Derivative Relationships in Inverses
Utilizing the derived slope relationship between functions and their inverses, we compute (f-1)'(3) for the function f(x) = x3 + x + 1. Since f'(x) = 3x2 + 1:
Evaluate f'(x) for x0 such that f(x0) = 3; thus, we derive the necessary value yielding f'(x0) which implies (f-1)'(3) = 1/f'(x0).
Conclusion
This exploration encompasses the derivatives of various functions including inverse trigonometric derivatives, linear functions, and demonstrates the fundamental concept regarding differentiability in relation to inverse functions.
References
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