Do question A ,B,C

Mathematics

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Here are the solutions for questions A, B, and C.

A) If f(x)=3x22x+1f(x) = 3x^2 - 2x + 1, find f(x)f'(x) from first principles.

Step 1: Write down the definition of the derivative from first principles and find f(x+h)f(x+h). The definition of the derivative is: f(x)=limh0f(x+h)f(x)hf'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h} Given f(x)=3x22x+1f(x) = 3x^2 - 2x + 1, we find f(x+h)f(x+h): f(x+h)=3(x+h)22(x+h)+1f(x+h) = 3(x+h)^2 - 2(x+h) + 1 f(x+h)=3(x2+2xh+h2)2x2h+1f(x+h) = 3(x^2 + 2xh + h^2) - 2x - 2h + 1 f(x+h)=3x2+6xh+3h22x2h+1f(x+h) = 3x^2 + 6xh + 3h^2 - 2x - 2h + 1

Step 2: Calculate f(x+h)f(x)f(x+h) - f(x). f(x+h)f(x)=(3x2+6xh+3h22x2h+1)(3x22x+1)f(x+h) - f(x) = (3x^2 + 6xh + 3h^2 - 2x - 2h + 1) - (3x^2 - 2x + 1) f(x+h)f(x)=3x2+6xh+3h22x2h+13x2+2x1f(x+h) - f(x) = 3x^2 + 6xh + 3h^2 - 2x - 2h + 1 - 3x^2 + 2x - 1 f(x+h)f(x)=6xh+3h22hf(x+h) - f(x) = 6xh + 3h^2 - 2h

Step 3: Divide by hh and simplify. f(x+h)f(x)h=6xh+3h22hh\frac{f(x+h) - f(x)}{h} = \frac{6xh + 3h^2 - 2h}{h} f(x+h)f(x)h=h(6x+3h2)h\frac{f(x+h) - f(x)}{h} = \frac{h(6x + 3h - 2)}{h} f(x+h)f(x)h=6x+3h2\frac{f(x+h) - f(x)}{h} = 6x + 3h - 2

Step 4: Take the limit as h0h \to 0. f(x)=limh0(6x+3h2)f'(x) = \lim_{h \to 0} (6x + 3h - 2) f(x)=6x+3(0)2f'(x) = 6x + 3(0) - 2 f(x)=6x2\boxed{f'(x) = 6x - 2}

B) Differentiate y=3x22x+1xy = \frac{3x^2 - 2x + 1}{\sqrt{x}} with respect to xx.

Step 1: Rewrite the function by expressing x\sqrt{x} as x1/2x^{1/2} and dividing each term in the numerator. y=3x2x1/22xx1/2+1x1/2y = \frac{3x^2}{x^{1/2}} - \frac{2x}{x^{1/2}} + \frac{1}{x^{1/2}} y=3x21/22x11/2+x1/2y = 3x^{2 - 1/2} - 2x^{1 - 1/2} + x^{-1/2} y=3x3/22x1/2+x1/2y = 3x^{3/2} - 2x^{1/2} + x^{-1/2}

Step 2: Differentiate each term using the power rule, ddx(axn)=anxn1\frac{d}{dx}(ax^n) = anx^{n-1}. dydx=ddx(3x3/2)ddx(2x1/2)+ddx(x1/2)\frac{dy}{dx} = \frac{d}{dx}(3x^{3/2}) - \frac{d}{dx}(2x^{1/2}) + \frac{d}{dx}(x^{-1/2}) dydx=3(32)x3212(12)x121+(12)x121\frac{dy}{dx} = 3 \left(\frac{3}{2}\right) x^{\frac{3}{2} - 1} - 2 \left(\frac{1}{2}\right) x^{\frac{1}{2} - 1} + \left(-\frac{1}{2}\right) x^{-\frac{1}{2} - 1} dydx=92x1/21x1/212x3/2\frac{dy}{dx} = \frac{9}{2} x^{1/2} - 1 x^{-1/2} - \frac{1}{2} x^{-3/2}

Step 3: Simplify the expression. \boxed{\frac{dy{dx} = \frac{9}{2} \sqrt{x} - \frac{1}{\sqrt{x}} - \frac{1}{2x\sqrt{x}}}}

C) Find the equation of the tangent to the curve y=x32x2+3x1y = x^3 - 2x^2 + 3x - 1 at the point where x=2x=2.

Step 1: Find the y-coordinate of the point of tangency. Substitute x=2x=2 into the equation of the curve: y=(2)32(2)2+3(2)1y = (2)^3 - 2(2)^2 + 3(2) - 1 y=82(4)+61y = 8 - 2(4) + 6 - 1 y=88+61y = 8 - 8 + 6 - 1 y=5y = 5 The point of tangency is (2,5)(2, 5).

Step 2: Find the derivative dydx\frac{dy}{dx} to determine the slope function. y=x32x2+3x1y = x^3 - 2x^2 + 3x - 1 dydx=3x22(2x)+3(1)0\frac{dy}{dx} = 3x^2 - 2(2x) + 3(1) - 0 dydx=3x24x+3\frac{dy}{dx} = 3x^2 - 4x + 3

Step 3: Evaluate the derivative at x=2x=2 to find the slope (mm) of the tangent. m=3(2)24(2)+3m = 3(2)^2 - 4(2) + 3 m=3(4)8+3m = 3(4) - 8 + 3 m=128+3m = 12 - 8 + 3 m=7m = 7

Step 4: Use the point-slope form of a linear equation, yy1=m(xx1)y - y_1 = m(x - x_1), to find the equation of the tangent. Using the point (x1,y1)=(2,5)(x_1, y_1) = (2, 5) and slope m=7m=7: y5=7(x2)y - 5 = 7(x - 2) y5=7x14y - 5 = 7x - 14 y=7x14+5y = 7x - 14 + 5 y=7x9\boxed{y = 7x - 9}

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