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IrinaK [193]
3 years ago
15

Using addition formula solve tan 15​

Mathematics
1 answer:
salantis [7]3 years ago
3 0

Answer:

2 - \sqrt{3}

Step-by-step explanation:

Using the addition formula for tangent

tan(A - B) = \frac{tanA-tanB}{1+tanAtanB} and the exact values

tan45° = 1 , tan60° = \sqrt{3} , then

tan15° = tan(60 - 45)°

tan(60 - 45)°

= \frac{tan60-tan45}{1+tan60tan45}

= \frac{\sqrt{3}-1 }{1+\sqrt{3} }

Rationalise the denominator by multiplying numerator/ denominator by the conjugate of the denominator.

The conjugate of 1 + \sqrt{3} is 1 - \sqrt{3}

= \frac{(\sqrt{3}-1)(1-\sqrt{3})  }{(1+\sqrt{3})(1-\sqrt{3})  } ← expand numerator/denominator using FOIL

= \frac{\sqrt{3}-3-1+\sqrt{3}  }{1-3}

= \frac{-4+2\sqrt{3} }{-2}

= \frac{-4}{-2} + \frac{2\sqrt{3} }{-2}

= 2 - \sqrt{3}

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alex41 [277]

Step-by-step explanation:

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5 0
3 years ago
What is 0.275 0.20 0.572 and 0.725 greatest to least
Andru [333]
.725 , .572 , .275, .2
You look at the first decimal place to see which is the greatest. 7 is greater than 5 and 2 so it's first. Then 5 is greater than 2 so it is next. For the last two numbers since 2 is the same value you look at the next decimal place. Since 7 is greater than 0 it comes next!
6 0
3 years ago
The function f(x) = –x2 – 4x + 5 is shown on the graph. On a coordinate plane, a parabola opens down. It goes through (negative
madam [21]

The true statement is:

"The range of the function is all real numbers less than or equal to 9."

<h3>Which statements are true?</h3>

Here we have the quadratic function:

f(x) = -x^2 - 4x + 5

And we want to see which of the given statements are true.

The first one is:

"The domain is al real numbers less than or equal to -2"

This is false, for all quadratic functions the domain is the set of all real numbers (unless the domain is defined).

The second statement is:

" The domain of the function is all real numbers less than or equal to 9."

Also false

Third one:

" The range of the function is all real numbers less than or equal to −2"

The range of a quadratic function with a negative leading coefficient will be the set of all the values smaller than the y-value of the vertex.

In this case, the quadratic function is:

f(x) = -x^2 - 4x + 5

So the vertex is at:

x = 4/(2*-1) = -2\\

Then the y-value of the vertex is:

f(-2) = -(-2)^2 - 4*(-2) + 5 = -4 + 8 + 5 = 9

So the range is the set of all real numbers less than or equal to 9.

So the above statement is false, and the final one:

"The range of the function is all real numbers less than or equal to 9."

Is the true statement.

If you want to learn more about quadratic functions:

brainly.com/question/1214333

#SPJ1

8 0
2 years ago
nora is planning a birthday party for her little sister, colleen. she needs to purchase 12 cupcakes she can not spend more than
Lapatulllka [165]

Answer:

if she cannot spend more than $40, she will spend .3 on each cupcake

Step-by-step explanation:

when you divide 12 by 40, you get .3 and to check if it is true, you can multiply .3 x 40 and you will get 12 hope you get it right, and have a good day :)

6 0
2 years ago
Point E is on line segment DF. Given DE<br> EF.<br> 6 and DF =9, determine the length EF
nlexa [21]

Answer:

<h2>3</h2>

Step-by-step explanation:

IF point E lies on the line segment DF, this means that all the points DEF are collinear and DE+EF = DF.

Given parameter

DE = 6

DF = 9

Required

EF

Substituting the given parameter into the expression above to get the required will be;

DE+EF = DF.

EF = DF-DE

EF = 9-6

EF = 3

Hence the length of EF is equivalent to 3

5 0
3 years ago
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