Mitglied: Rom

Quote:
after half of the formula I have, -3 - Sqrt +9-4 /2*1.. my question is simple and two part.

1) to Sqrt the 9 I must also Sqrt the 4 or calculate the sum of 9-4 then Sqrt before manipulating change from outside the Sqrt right?

2) please insert parenthesis to solve including signs.

if this is the quadratic formula evaluated for a=1, b=3, and c=4

then notated properly it is

[size=200]([/size]-3 +/- sqrt[size=150]([/size]9 - 4[size=150])[/size][size=200])/[/size](2*1)

so to answer (1) you subtract the 4 from 9 to get 5 and then take the square root

(2) is answered by the formula above.

Rom13.02.2014

+6251

Quote:
what is -1.2 turned into a fraction

-1.2 =
-(1.2) =
-(1 2/10) =
-(10/10 + 2/10) =
-(12/10) =
-12/10

alternatively you can just multiply the decimal by 1 in the form of 10/10

(-1.2) =
1*(-1.2) =
(10/10)*(-1.2) =
(10 * -1.2)/10 =
-12/10

Rom13.02.2014

+6251

Quote:
Solve the equation bolow given that 0 < x < 2pi
cos2x + 1/2 = 0
(sqrt(3) tan x + 1)(2 sinx - sqrt(3)) = 0

for the 1st one

cos(2x) = 2cos ²(x)-1

cos(2x) + 1/2 = 0
2cos ²(x) - 1 + (1/2) = 0
2cos ²(x) - (1/2) = 0
2cos ²(x) = 1/2
cos ²(x) = 1/4
cos(x) = +/- sqrt(1/4)
cos(x) = +/- 1/2
x = pi/3, 2pi/3, 4pi/3, 5pi/3

for the second one

(sqrt(3) tan x + 1)(2 sinx - sqrt(3)) = 0

this is true if either of the factors is 0 so

(sqrt(3)tan(x)+1) = 0 OR (2sin(x)-sqrt(3)) = 0

(sqrt(3)tan(x)+1) = 0
tan(x) = -1/sqrt(3)
x = arctan(-1/sqrt(3)) = 5pi/6, 11pi/6

(2sin(x) - sqrt(3)) = 0
sin(x) = sqrt(3)/2
x = arcsin(sqrt(3)/2) = pi/3, 2pi/3

so x = pi/3, 5pi/6, 2pi/3, 11pi/6 all satisfy the second equation

Rom13.02.2014

+6251

Quote:
Nelson charged $542.95 for a new printer on May 12 and $56.79 for a restaurant bill on May 22. Calculate the interest charged, at 19.5% simple interest, on the payment date of June 21st.
(RECALL: I = PrT)

Okay, so I am having troubles figuring out how to calculate this. Examples I have are helpful to a point, but unfortunately do not show me exactly what to do. :/ Please help.

The trick here is to note that the interest is annual but you have a fraction of a year as the period.
You have to make some assumptions here. I'm guessing that they intend the interest to start accumulating from the day of the transaction.

You just have to treat each one separately

June 21 - May 12 = 40 days = 40/365 yrs

so the interest due on the printer is $542.95 * (0.195) * (40/365) = $11.60

June 21 - May 22 = 30 days = 30/365 yrs

so the interest due on the meal is $56.79 * (0.195) * (30/365) = $0.91

the total interest is just the sum of these i.e. $12.51

Rom13.02.2014

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