What is 20/7 as a mixed number in simplest form?

Can anybody show me how to do this half angle identity problem STEP BY STEP? I always seem to be missing something

klio [65]

Answer: $\bold{-\dfrac{7\sqrt2}{10}}$

Step-by-step explanation:

It is given that θ is between 270° and 360°, which means that θ is located in Quadrant IV ⇒ (x > 0, y < 0). Furthermore, the half-angle will be between 135° and 180°, which means the half-angle is in Quadrant II ⇒ $cos\ \dfrac{\theta}{2}$

It is given that sin θ = $-\dfrac{7}{25}$ ⇒ y = -7 & hyp = 25

Use Pythagorean Theorem to find "x":

x² + y² = hyp²

x² + (-7)² = 25²

x² + 49 = 625

x² = 576

x = 24

Use the "x" and "hyp" values to find cos θ:

$cos\ \theta=\dfrac{x}{hyp}=\dfrac{24}{25}$

Lastly, input cos θ into the half angle formula:

$cos\bigg(\dfrac{\theta}{2}\bigg)=\pm \sqrt{\dfrac{1+cos\ \theta}{2}}\\\\\\.\qquad \quad =\pm \sqrt{\dfrac{1+\dfrac{24}{25}}{2}}\\\\\\.\qquad \quad =\pm \sqrt{\dfrac{\dfrac{25}{25}+\dfrac{24}{25}}{2}}\\\\\\.\qquad \quad =\pm \sqrt{\dfrac{\dfrac{49}{25}}{2}}\\\\\\.\qquad \quad =\pm \sqrt{\dfrac{49}{50}}\\\\\\.\qquad \quad =\pm \dfrac{7}{5\sqrt2}}\\\\\\.\qquad \quad =\pm \dfrac{7}{5\sqrt2}}\bigg(\dfrac{\sqrt2}{\sqrt2}\bigg)\\\\\\.\qquad \quad =\pm \dfrac{7\sqrt2}{10}$

Reminder: We previously determined that the half-angle will be negative.

6 0

2 years ago

The family wants to determine if they can drive to the national park using Just one tank of gas in their car. Determine whether

Nataliya [291]

Answer:

The Fullers can reach the national park

Step-by-step explanation:

The complete question is

The Fuller family wants to drive to a national park. Some information about their trip is given in the table below.

Distance to national park 515 miles

Car’s gas tank capacity 20 gallons

Average gas mileage for car 26 miles per gallon

The family wants to determine if they can drive to the national park using just one tank of gas in their car. Determine whether the Fullers can reach the national park. Show your work or explain your answer.

we know that

The Average gas mileage for the car is 26 miles per gallon

That means

With 1 gallon the car runs 26 miles

so

using a proportion

Find out how many miles the car runs with 20 gallons (one tank of gas)

$\frac{26}{1}\ \frac{miles}{gallon}=\frac{x}{20}\ \frac{miles}{gallons}\\\\x=26(20)\\\\x=520\ miles$