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2 years ago

If a+1/a=3 then find the value of a-1/a

Mathematics

1 answer:

kenny6666 [7]2 years ago

4 0

Answer:

√5

Step-by-step explanation:

Given a + 1/a = 3, find its square:

a² + 2a*1/a + 1/a² = 9
a² + 1/a² = 9 - 2 = 7

Now find the square of (a - 1/a):

a² - 2a*1/a + 1/a² =
a² + 1/a² - 2

Substitute the value from the first square:

7 - 2 = 5

Since (a - 1/a)² = 5, its square root is:

a - 1/a = √5

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3 years ago

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In a circus performance, a monkey is strapped to a sled and both are given an initial speed of 3.0 m/s up a 22.0° inclined track

Aloiza [94]

Answer:

Approximately $0.31\; \rm m$ , assuming that $g = 9.81\; \rm N \cdot kg^{-1}$ .

Step-by-step explanation:

Initial kinetic energy of the sled and its passenger:

$\begin{aligned}\text{KE} &= \frac{1}{2}\, m \cdot v^{2} \\ &= \frac{1}{2} \times 14\; \rm kg \times (3.0\; \rm m\cdot s^{-1})^{2} \\ &= 63\; \rm J\end{aligned}$ .

Weight of the slide:

$\begin{aligned}W &= m \cdot g \\ &= 14\; \rm kg \times 9.81\; \rm N \cdot kg^{-1} \\ &\approx 137\; \rm N\end{aligned}$ .

Normal force between the sled and the slope:

$\begin{aligned}F_{\rm N} &= W\cdot \cos(22^{\circ}) \\ &\approx 137\; \rm N \times \cos(22^{\circ}) \\ &\approx 127\; \rm N\end{aligned}$ .

Calculate the kinetic friction between the sled and the slope:

$\begin{aligned} f &= \mu_{k} \cdot F_{\rm N} \\ &\approx 0.20\times 127\; \rm N \\ &\approx 25.5\; \rm N\end{aligned}$ .

Assume that the sled and its passenger has reached a height of $h$ meters relative to the base of the slope.

Gain in gravitational potential energy:

$\begin{aligned}\text{GPE} &= m \cdot g \cdot (h\; {\rm m}) \\ &\approx 14\; {\rm kg} \times 9.81\; {\rm N \cdot kg^{-1}} \times h\; {\rm m} \\ & \approx (137\, h)\; {\rm J} \end{aligned}$ .

Distance travelled along the slope:

$\begin{aligned}x &= \frac{h}{\sin(22^{\circ})} \\ &\approx \frac{h\; \rm m}{0.375}\end{aligned}$ .

The energy lost to friction (same as the opposite of the amount of work that friction did on this sled) would be:

$\begin{aligned} & - (-x)\, f \\ = \; & x \cdot f \\ \approx \; & \frac{h\; {\rm m}}{0.375}\times 25.5\; {\rm N} \\ \approx\; & (68.1\, h)\; {\rm J}\end{aligned}$ .

In other words, the sled and its passenger would have lost (approximately) $((137 + 68.1)\, h)\; {\rm J}$ of energy when it is at a height of $h\; {\rm m}$ .

The initial amount of energy that the sled and its passenger possessed was $\text{KE} = 63\; {\rm J}$ . All that much energy would have been converted when the sled is at its maximum height. Therefore, when $h\; {\rm m}$ is the maximum height of the sled, the following equation would hold.

$((137 + 68.1)\, h)\; {\rm J} = 63\; {\rm J}$ .

Solve for $h$ :

$(137 + 68.1)\, h = 63$ .

$\begin{aligned} h &= \frac{63}{137 + 68.1} \approx 0.31\; \rm m\end{aligned}$ .

Therefore, the maximum height that this sled would reach would be approximately $0.31\; \rm m$ .

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2 years ago

Marge purchased bicycle helmets and tire pumps. Each helmet cost $12.00 and each pump cost $8.00. She purchased a total of 18 it

algol [13]

Answer:

Step-by-step explanation:

Let the no. of helmet be x

cost of 1 helmet = $12.00

cost of x helmet = $12.00*x = $12x

Let the no. of tire pumps be y

cost of 1 tire pumps = $8.00

cost of x tire pumps = $8.00*y = $8y

Given that total no. of helmet and pump is 18

thus

x + y = 18

y = 18-x

also given

total money spent is $188

thus

12x+8y = 188

using y = 18 - x

we have

12x + 8(18-x) = 188

=> 12x+ 144 - 8x = 188

=> 4x = 188-144 = 44

=> x = 44/4 = 11

Thus, no of helmet bought by Margo is 11.

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2 years ago

If a+1/a=3 then find the value of a-1/a​

If a+1/a=3 then find the value of a-1/a