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2 years ago

Please help me :) I need help

Mathematics

2 answers:

zzz [600]2 years ago

7 0

Answer:

Option C

brainly plz :)

Ilia_Sergeevich [38]2 years ago

5 0

It is C! 3lbs of cherries + 2lbs of apples = 28 and 2lbs of cherries + 1lb of apples = 17!

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Complete the identity.<br> 1) sec^4 x + sec^2 x tan^2 x - 2 tan^4 x = ?

Alecsey [184]

Answer:

See Explanation

Step-by-step explanation:

<em>Question like this are better answered if there are list of options; However, I'll simplify as far as the expression can be simplified</em>

Given

$sec^4 x + sec^2 x tan^2 x - 2 tan^4 x$

Required

Simplify

$(sec^2 x)^2 + sec^2 x tan^2 x - 2 (tan^2 x)^2$

Represent $sec^2x$ with a

Represent $tan^2x$ with b

The expression becomes

$a^2 + ab- 2 b^2$

Factorize

$a^2 + 2ab -ab- 2 b^2$

$a(a + 2b) -b(a+ 2 b)$

$(a -b) (a+ 2 b)$

Recall that

$a = sec^2x$

$b = tan^2x$

The expression $(a -b) (a+ 2 b)$ becomes

$(sec^2x -tan^2x) (sec^2x+ 2 tan^2x)$

..............................................................................................................................

In trigonometry

$sec^2x =1 +tan^2x$

Subtract $tan^2x$ from both sides

$sec^2x - tan^2x =1 +tan^2x - tan^2x$

$sec^2x - tan^2x =1$

..............................................................................................................................

Substitute 1 for $sec^2x - tan^2x$ in $(sec^2x -tan^2x) (sec^2x+ 2 tan^2x)$

$(1) (sec^2x+ 2 tan^2x)$

Open Bracket

$sec^2x+ 2 tan^2x$ ------------------This is an equivalence

$(secx)^2+ 2 (tanx)^2$

Solving further;

................................................................................................................................

In trigonometry

$secx = \frac{1}{cosx}$

$tanx = \frac{sinx}{cosx}$

Substitute the expressions for secx and tanx

................................................................................................................................

$(secx)^2+ 2 (tanx)^2$ becomes

$(\frac{1}{cosx})^2+ 2 (\frac{sinx}{cosx})^2$

Open bracket

$\frac{1}{cos^2x}+ 2 (\frac{sin^2x}{cos^2x})$

$\frac{1}{cos^2x}+ \frac{2sin^2x}{cos^2x}$

Add Fraction

$\frac{1 + 2sin^2x}{cos^2x}$ ------------------------ This is another equivalence

................................................................................................................................

In trigonometry

$sin^2x + cos^2x= 1$

Make $sin^2x$ the subject of formula

$sin^2x= 1 - cos^2x$

................................................................................................................................

Substitute the expressions for $1 - cos^2x$ for $sin^2x$

$\frac{1 + 2(1 - cos^2x)}{cos^2x}$

Open bracket

$\frac{1 + 2 - 2cos^2x}{cos^2x}$

$\frac{3 - 2cos^2x}{cos^2x}$ ---------------------- This is another equivalence

8 0

3 years ago

Which expression is NOT equivalent to −38⋅(−4+12)? Drag this expression to the box.

lesya [120]

I had this question so here's the answer and explanation! :)

Answer:

The answer to your question is the first option :D

Step-by-step explanation:

Original expression

-3/8 (-4 + 1/2)

First option -3/8 (-4) + (3/8)(1/2) This option is not equivalent because

they forgot the negative sign of the

second term.

Second option (-3/8)(-4) + (-3/8)(1/2) This option is equivalent to the

original. Distributive property

Third option (-3/2)(-3 1/2) This option is equivalent to the original

Fourth option (-3/8)(-3) + (-3/8)(-1/2) This option is equivalent to the original

HOPE THIS HELPS :)

5 0

2 years ago

Read 2 more answers

Please I need some answers

kumpel [21]

Answer:

If you add any number to itself, the result is divisible by 2.

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3 years ago

Rita is hosting movie night tonight. To get ready, she makes popcorn. She fills both a small bowl and a large bowl to the top wi

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Answer: The smaller bowl

Explanation: in the big bowl there is more popcorn which means it will need more even salt to be saltier.

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2 years ago

What is a coefficient

Bumek [7]

Answer:

a coefficient is the number before a variable for example in 18x 18 is the coefficient or in 27y its 27

Step-by-step explanation:

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3 years ago