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2 years ago

Help me with this please

Mathematics

1 answer:

Leya [2.2K]2 years ago

6 0

Answer:

280

Step-by-step explanation:

what i did was just go step by step in what your teacher tells you to do but i am going to say this may be wrong.

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If sinA=√3-1/2√2,then prove that cos2A=√3/2 prove that

Ivan

Answer:

$\boxed{\sf cos2A =\dfrac{\sqrt3}{2}}$

Step-by-step explanation:

Here we are given that the value of sinA is √3-1/2√2 , and we need to prove that the value of cos2A is √3/2 .

Given :-

• $\sf\implies sinA =\dfrac{\sqrt3-1}{2\sqrt2}$

To Prove :-

• $\sf\implies cos2A =\dfrac{\sqrt3}{2}$

Proof :-

We know that ,

$\sf\implies cos2A = 1 - 2sin^2A$

Therefore , here substituting the value of sinA , we have ,

$\sf\implies cos2A = 1 - 2\bigg( \dfrac{\sqrt3-1}{2\sqrt2}\bigg)^2$

Simplify the whole square ,

$\sf\implies cos2A = 1 -2\times \dfrac{ 3 +1-2\sqrt3}{8}$

Add the numbers in numerator ,

$\sf\implies cos2A = 1-2\times \dfrac{4-2\sqrt3}{8}$

Multiply it by 2 ,

$\sf\implies cos2A = 1 - \dfrac{ 4-2\sqrt3}{4}$

Take out 2 common from the numerator ,

$\sf\implies cos2A = 1-\dfrac{2(2-\sqrt3)}{4}$

Simplify ,

$\sf\implies cos2A = 1 -\dfrac{ 2-\sqrt3}{2}$

Subtract the numbers ,

$\sf\implies cos2A = \dfrac{ 2-2+\sqrt3}{2}$

Simplify,

$\sf\implies \boxed{\pink{\sf cos2A =\dfrac{\sqrt3}{2}} }$

Hence Proved !

8 0

3 years ago

You randomly choose two bills from your wallet. What is the probability that they are both $20 bills. There are two 20's, one 10

Softa [21]

Answer:

2/6 or 33.33%

Explanation:

There are 6 numbers all together and 2 of them are 20$.As a fraction this would look like 2/6. 2/6 is also 33.33% of the wallet and its also the probability of pulling out a $20 bill

7 0

3 years ago

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How to find the value of x so the polygons have the same perimeter

Scorpion4ik [409]

I hope this helps you

6 0

3 years ago

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Due to gravity, objects weigh three times as much on Earth as they do on Mercury.

SpyIntel [72]

Answer:

If an object on Mercury weighed 25lb, it would weigh 75lb on Earth

(25 * 3 = 75)

The answer is b

:")

6 0

3 years ago

Water coming out from a fountain is modeled by the function f(x) = -x2 + 5x + 4 where f(x) represents the height, in feet, of th

slava [35]

F ( x ) = - x² + 5 x + 4
between x = 3 and x = 5:
f ( 3 ) = - 3² + 5 · 3 + 4 = - 9 + 15 + 4 = 10
f ( 5 ) = - 5² + 5 · 5 + 4 = - 25 + 25 + 4 = 4
Average rate of change:
( 4 - 10 ) / ( 5 - 3 ) = - 6 : 2 = - 3 feet / sec

6 0

3 years ago