A) If f(x)=3x2−2x+1, find f′(x) from first principles.
Step 1: Write down the definition of the derivative from first principles and find f(x+h).
The definition of the derivative is:
f′(x)=limh→0hf(x+h)−f(x)
Given f(x)=3x2−2x+1, we find f(x+h):
f(x+h)=3(x+h)2−2(x+h)+1f(x+h)=3(x2+2xh+h2)−2x−2h+1f(x+h)=3x2+6xh+3h2−2x−2h+1
Step 3: Divide by h and simplify.
hf(x+h)−f(x)=h6xh+3h2−2hhf(x+h)−f(x)=hh(6x+3h−2)hf(x+h)−f(x)=6x+3h−2
Step 4: Take the limit as h→0.
f′(x)=limh→0(6x+3h−2)f′(x)=6x+3(0)−2f′(x)=6x−2
B) Differentiate y=x3x2−2x+1 with respect to x.
Step 1: Rewrite the function by expressing x as x1/2 and dividing each term in the numerator.
y=x1/23x2−x1/22x+x1/21y=3x2−1/2−2x1−1/2+x−1/2y=3x3/2−2x1/2+x−1/2
Step 2: Differentiate each term using the power rule, dxd(axn)=anxn−1.
dxdy=dxd(3x3/2)−dxd(2x1/2)+dxd(x−1/2)dxdy=3(23)x23−1−2(21)x21−1+(−21)x−21−1dxdy=29x1/2−1x−1/2−21x−3/2
C) Find the equation of the tangent to the curve y=x3−2x2+3x−1 at the point where x=2.
Step 1: Find the y-coordinate of the point of tangency.
Substitute x=2 into the equation of the curve:
y=(2)3−2(2)2+3(2)−1y=8−2(4)+6−1y=8−8+6−1y=5
The point of tangency is (2,5).
Step 2: Find the derivative dxdy to determine the slope function.
y=x3−2x2+3x−1dxdy=3x2−2(2x)+3(1)−0dxdy=3x2−4x+3
Step 3: Evaluate the derivative at x=2 to find the slope (m) of the tangent.
m=3(2)2−4(2)+3m=3(4)−8+3m=12−8+3m=7
Step 4: Use the point-slope form of a linear equation, y−y1=m(x−x1), to find the equation of the tangent.
Using the point (x1,y1)=(2,5) and slope m=7:
y−5=7(x−2)y−5=7x−14y=7x−14+5y=7x−9
That's 2 down. 3 left today — send the next one.
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This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.
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Here are the solutions for questions A, B, and C. A) If f(x) = 3x^2 - 2x + 1, find f'(x) from first principles. Step 1: Write down the definition of the derivative from first principles and find f(x+h). The definition of the derivative is: f'(x) = _h 0 (f(x+h) - f(x))/(h) Given f(x) = 3x^2 - 2x + 1, we find f(x+h): f(x+h) = 3(x+h)^2 - 2(x+h) + 1 f(x+h) = 3(x^2 + 2xh + h^2) - 2x - 2h + 1 f(x+h) = 3x^2 + 6xh + 3h^2 - 2x - 2h + 1 Step 2: Calculate f(x+h) - f(x). f(x+h) - f(x) = (3x^2 + 6xh + 3h^2 - 2x - 2h + 1) - (3x^2 - 2x + 1) f(x+h) - f(x) = 3x^2 + 6xh + 3h^2 - 2x - 2h + 1 - 3x^2 + 2x - 1 f(x+h) - f(x) = 6xh + 3h^2 - 2h Step 3: Divide by h and simplify. (f(x+h) - f(x))/(h) = (6xh + 3h^2 - 2h)/(h) (f(x+h) - f(x))/(h) = (h(6x + 3h - 2))/(h) (f(x+h) - f(x))/(h) = 6x + 3h - 2 Step 4: Take the limit as h 0. f'(x) = _h 0 (6x + 3h - 2) f'(x) = 6x + 3(0) - 2 f'(x) = 6x - 2 B) Differentiate y = (3x^2 - 2x + 1)/(sqrt(x)) with respect to x. Step 1: Rewrite the function by expressing sqrt(x) as x^1/2 and dividing each term in the numerator. y = (3x^2)/(x^1/2) - (2x)/(x^1/2) + (1)/(x^1/2) y = 3x^2 - 1/2 - 2x^1 - 1/2 + x^-1/2 y = 3x^3/2 - 2x^1/2 + x^-1/2 Step 2: Differentiate each term using the power rule, (d)/(dx)(ax^n) = anx^n-1. (dy)/(dx) = (d)/(dx)(3x^3/2) - (d)/(dx)(2x^1/2) + (d)/(dx)(x^-1/2) (dy)/(dx) = 3 ((3)/(2)) x^(3)/(2) - 1 - 2 ((1)/(2)) x^(1)/(2) - 1 + (-(1)/(2)) x^-(1)/(2) - 1 (dy)/(dx) = (9)/(2) x^1/2 - 1 x^-1/2 - (1)/(2) x^-3/2 Step 3: Simplify the expression. (dy)/(dx) = (9)/(2) sqrt(x) - (1)/(sqrt(x)) - (1)/(2xsqrt(x)) C) Find the equation of the tangent to the curve y = x^3 - 2x^2 + 3x - 1 at the point where x=2. Step 1: Find the y-coordinate of the point of tangency. Substitute x=2 into the equation of the curve: y = (2)^3 - 2(2)^2 + 3(2) - 1 y = 8 - 2(4) + 6 - 1 y = 8 - 8 + 6 - 1 y = 5 The point of tangency is (2, 5). Step 2: Find the derivative (dy)/(dx) to determine the slope function. y = x^3 - 2x^2 + 3x - 1 (dy)/(dx) = 3x^2 - 2(2x) + 3(1) - 0 (dy)/(dx) = 3x^2 - 4x + 3 Step 3: Evaluate the derivative at x=2 to find the slope (m) of the tangent. m = 3(2)^2 - 4(2) + 3 m = 3(4) - 8 + 3 m = 12 - 8 + 3 m = 7 Step 4: Use the point-slope form of a linear equation, y - y_1 = m(x - x_1), to find the equation of the tangent. Using the point (x_1, y_1) = (2, 5) and slope m=7: y - 5 = 7(x - 2) y - 5 = 7x - 14 y = 7x - 14 + 5 y = 7x - 9 That's 2 down. 3 left today — send the next one.