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3 years ago

Help me plz I need to finish these test corrections toooddayyyy

Mathematics

1 answer:

Dafna1 [17]3 years ago

3 0

Answer:

I thank it is B.

Step-by-step explanation:

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Let f(x) = 1/x^2 (a) Use the definition of the derivatve to find f'(x). (b) Find the equation of the tangent line at x=2

Verdich [7]

Answer:

(a) $f'(x)=-\frac{2}{x^3}$

(b) $y=-0.25x+0.75$

Step-by-step explanation:

The given function is

$f(x)=\frac{1}{x^2}$ .... (1)

According to the first principle of the derivative,

$f'(x)=lim_{h\rightarrow 0}\frac{f(x+h)-f(x)}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{\frac{1}{(x+h)^2}-\frac{1}{x^2}}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{\frac{x^2-(x+h)^2}{x^2(x+h)^2}}{h}$

$f'(x)=lim_{h\rightarrow 0}\frac{x^2-x^2-2xh-h^2}{hx^2(x+h)^2}$

$f'(x)=lim_{h\rightarrow 0}\frac{-2xh-h^2}{hx^2(x+h)^2}$

$f'(x)=lim_{h\rightarrow 0}\frac{-h(2x+h)}{hx^2(x+h)^2}$

Cancel out common factors.

$f'(x)=lim_{h\rightarrow 0}\frac{-(2x+h)}{x^2(x+h)^2}$

By applying limit, we get

$f'(x)=\frac{-(2x+0)}{x^2(x+0)^2}$

$f'(x)=\frac{-2x)}{x^4}$

$f'(x)=\frac{-2)}{x^3}$ .... (2)

Therefore $f'(x)=-\frac{2}{x^3}$ .

(b)

Put x=2, to find the y-coordinate of point of tangency.

$f(x)=\frac{1}{2^2}=\frac{1}{4}=0.25$

The coordinates of point of tangency are (2,0.25).

The slope of tangent at x=2 is

$m=(\frac{dy}{dx})_{x=2}=f'(x)_{x=2}$

Substitute x=2 in equation 2.

$f'(2)=\frac{-2}{(2)^3}=\frac{-2}{8}=\frac{-1}{4}=-0.25$

The slope of the tangent line at x=2 is -0.25.

The slope of tangent is -0.25 and the tangent passes through the point (2,0.25).

Using point slope form the equation of tangent is

$y-y_1=m(x-x_1)$

$y-0.25=-0.25(x-2)$

$y-0.25=-0.25x+0.5$

$y=-0.25x+0.5+0.25$

$y=-0.25x+0.75$

Therefore the equation of the tangent line at x=2 is y=-0.25x+0.75.

5 0

3 years ago

6/4 = 8/blank please help me

oksian1 [2.3K]

Answer:

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

Solve by using any method of substitution<br><br>4 +8x = y <br>6x - y = 2

Bumek [7]

Answer:

(-3,-20)

Step-by-step explanation:

4 +8x = y ...... equation (1)

6x - y = 2 ........equation(2)

from equation 2

6x - y = 2

6x -(4+8x) =2

6x - 4 + 8x = 2

+4 +4

6x - 8x = 6

-2x=6

divide by -2

x= -3

put x in equation (1) to solve for y

4 + 8x = y

4+8(-3)=y

4-24=y

-20=y

y= -20

solution = (-3,-20)

8 0

3 years ago

Describe in detail how you would create a number line with the following points: 4, 1.25, the opposite of 3, and – (–2fraction o

MAVERICK [17]

Answer:

Look at the whole numbers and not the tenths hundreds and stuff. 1,2,3.25 and then fraction.

Step-by-step explanation:

6 0

3 years ago

What does powers of fractions mean <br> we learned it today and i didn't get it

Leokris [45]

Its same as powers of a whole number.
Lets take example
(1/2)²=1/2×1/2=1/4
We can write it in a different way (0.5)²=0.5×0.5=0.25

4 0

3 years ago