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il63 [147K]
1 year ago
11

Prove that Cos4x=8Cosx -8Cosx​

Mathematics
1 answer:
harkovskaia [24]1 year ago
8 0
Please see the image attached

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The sum of two numbers a and b is 7 and the difference between them is 2. What is the value of a x b ? Give your answer as a mix
Andre45 [30]

Answer:

45/4

Step-by-step explanation:

We can interpret the question to have two equation which can be solve simultaneously

a+b=7------------(1)

a-b=2------------(2)

From eqn(2) make a subject of formula

a=2+b--------(3)

Substitute the (3) into eqn(1)

a+b=7------------(1)

2+b+b=7

2b=7-2

2b=5

b=5/2

From equation (3) substitute value of b to find a

a=2+b--------(3)

a= 2+5/2

a=9/2

Then What is the value of a x b ?

9/2× 5/2

=45/4

8 0
2 years ago
Lenny and Lisa have obtained a 30-year, fixed rate mortgage for $675,250 with a 7.25% interest rate. They purchased 3 points and
Vikentia [17]

Answer:

119 months

Step-by-step explanation:

In this question, we are asked to calculate the amount of time it would take for a break-even point on a mortgage, if there is a factoring in the cost of points.

We proceed to answer the;

Mathematically,

The Break Even Point = Amount Paid for purchasing Discount Points divided by Monthly savings in the interest payments

We lost out the important values given in the question as follows:

Amount of Mortgage - $675,250

Tenure - 30 Years

The Rate of interest without points = 7.25%

The number of points = 3 points

The rate of interest with the 3 points = 6.875%

The amount to be paid for purchasing the discount point is now calculated below;

Since 1 discount point = 1% of mortgage value;

Therefore, 3 discount points = 3% of mortgage value

The amount paid is thus = 3% of $675,250 = $20,257.5

To calculate Monthly payment without points, we use the mathematical formula;

M = P[r(1+r)^n/((1+r)^n)-1)]

Where M

Is monthly payment, r is the interest rate, n is the number of months.

According to the question M = 675,250, r = 7.25% = 7.25/100 = 0.0725 , n= 30 * 12 months = 360 months

M = 675,250[0.0725(0.0725+1)^30/(1+0.0725)^360)-1) = $4606.40

To get the monthly payment with points, we simply use the formula again but this time interest rates will be 6.875% = 0.06875 I.e r = 0.06875

Inputting the terms in the formula will yield a value of $4435.91. This means monthly payment with discount will be $4435.91

Savings in monthly payments after purchasing the discount points = $4,606.40 - $4,435.91 = $170.48

Break Even = Purchase cost of Discount Points / Monthly savings

= $20,257.5 / $170.48

= 119 Months

Hence, the number of months it will take Lisa and Lenny to break-even point on their mortgage will be 119 months

6 0
3 years ago
What is the number of diagonals that intersect at a given vertex of a hexagon, heptagon, 30-gon and n-gon?
DENIUS [597]

Answer:

i. 9

ii. 14

iii. 405

iv. \frac{n(n-3)}{2}

Step-by-step explanation:

The number of diagonals in a polygon of n sides can be determined by:

\frac{n(n-3)}{2}

where n is the number of its sides.

i. For a hexagon which has 6 sides,

number of diagonals = \frac{6(6-3)}{2}

                                   = \frac{18}{2}

                                   = 9

The number of diagonals in a hexagon is 9.

ii. For a heptagon which has 7 sides,

number of diagonals = \frac{7(7-3)}{2}

                                   = \frac{28}{2}

                                   = 14

The number of diagonals in a heptagon is 14.

iii. For a 30-gon;

number of diagonals = \frac{30(30-3)}{2}

                                          = \frac{810}{2}

                                         = 405

The number of diagonals in a 30-gon is 405.

iv. For a n-gon,

number of diagonals = \frac{n(n-3)}{2}

The number of diagonals in a n-gon is \frac{n(n-3)}{2}

7 0
3 years ago
I am so confused please
sashaice [31]
1) 8a
2) 2x
3) 8k
4) 19.25c
5) 11y-5
6) .25x+2
7) 7t+14
8) 3.2k+5
9) z+6x
10) 3n+4p
11) 2y+2x
12) 27g-3s
13) 11m+100
14) 2w+12
15) 3b+10
16) 7a+6
17) 16n+10
18) 3y+6x
19) 15p/2
20) 3s-2t
6 0
3 years ago
Read 2 more answers
Complete the square: x2 - 6x + Blank = -13 + Blank​
kirza4 [7]

Answer:

x^2 - 6x + 9 = (x-3)^2

Step-by-step explanation:

4 0
2 years ago
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