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2 years ago

Which of the following are solutions to the equation 2cos2x-1=0

Mathematics

1 answer:

loris [4]2 years ago

8 0

Answer:

x = π/4 and 5π/4

Step-by-step explanation:

Given the expression;

2cos²x - 1 = 0

2cos²x = 0+1

2cos²x = 1

cos²x = 1/2

cos x = ±√1/2

cos x = ±0.7071

x = arccos(±0.7071)

x = ±45 degrees

Convert to radians

Sence 180° = π rad

45° = x

x = 45π/180

x = π/4

If x = -45°

Since cos is negative in the 3rd quadrant

x = 180 + 45

x = 225°

x = 225π/180

x = 45π/36

x = 5π/4

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andrew11 [14]

Answer:

sorry

Step-by-step explanation:

I cant

7 0

2 years ago

Need help asap important! thanks so much!

a_sh-v [17]

Answer:

You would have $343.37 at the end of the 2 years.

Step-by-step explanation:

Interest earned is like bonus money the bank pays you just for keeping money

$\mathrm{Compund\:Interest\:Formula}:\quad A = P { \left( 1+ \dfrac{ r }{ n } \right) }^{ nt }$

P: the starting balance of the account (also called initial deposit, or principal)

A: the new balance in the account after N years.

t: the number of years or time

r: the interest rate, (in decimal form)

n: the number of times the interest is compounded each year.

Annually = each year = 1

P =$300, r = 7%, t = 2, n = 1, A = ?

Substitute the numbers into the "Compound Interest Formula".

$A = 300 { \left( 1+ \dfrac{ 0.07 }{ 1 } \right) }^{ 1 \times 2 }$

$\mathrm{Anything\:divided\:by\:1\:gives\:itself}$

$A = 300 { \left( 1+0.07 \right) }^{ 1 \times 2 }$

$\mathrm{Add\:1\:and\:0.07\:to\:get\:1.07}$

$A = 300 \times { 1.07 }^{ 1 \times 2 }$

$\mathrm{Multiply\:1\:and\:2\:to\:get\:2}$

$A = 300 \times { 1.07 }^{ 2 }$

$\mathrm{Calculate\:1.07\:to\:the\:power\:of\:2\:and\:get\:1.1449}$

$A = 300 \times 1.1449$

$\mathrm{Multiply\:300\:and\:1.1449\:to\:get\:343.47}$

$A = 343.47$

So you would have $343.37 at the end of the 2 years.

Look at the chart

$\mathrm{Year}\quad \mathrm{Year\: Interest}\quad \mathrm{Total\:Interest}\quad \mathrm{Balance}\\\quad1\quad\quad\quad $21.00\quad\quad\quad\quad $21.00\quad\quad\quad\quad $321.00\\\quad2\quad\quad\quad $22.47\quad\quad\quad\quad $43.47\quad\quad\quad\quad $343.47$