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2 years ago

Evaluate the expression 6.2 - (-9.1).

Mathematics

1 answer:

cestrela7 [59]2 years ago

6 0

Answer: 15.1

Step-by-step explanation: subtracting a negative (ex. 1 - (-1)) just change to addition (prev. ex. would be 1+1) (also adding decimals is like adding normal numbers just remember the place values

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If tanA+sinA=m and tanA-sinA=n.prove that m^2-n^2=4√mn

mash [69]

Let $a=\tan A$ and $b=\sin A$ . Then

$m^2-n^2=(a+b)^2-(a-b)^2=(a^2+2ab+b^2)-(a^2-2ab+b^2)=4ab$

$\implies m^2-n^2=4\tan A\sin A$

and

$mn=(a+b)(a-b)=a^2-b^2$

$\implies4\sqrt{mn}=4\sqrt{\tan^2A-\sin^2A}$

The expression under the square root can be rewritten as

$\tan^2A-\sin^2A=\dfrac{\sin^2A}{\cos^2A}-\sin^2A=\sin^2A\left(\dfrac1{\cos^2A}-1\right)=\sin^2A(\sec^2A-1)$

Recall that

$\sin^2A+\cos^2A=1\implies\tan^2A+1=\sec^2A$

so that

$\tan^2A-\sin^2A=\sin^2A\tan^2A$

and assuming $\sin A>0$ and $\tan A>0$ , we end up with

$4\sqrt{\tan^2A-\sin^2A}=4\tan A\sin A$

so that

$m^2-n^2=4\sqrt{mn}$

as required.

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3 years ago

33% of what number is 1.45

Luba_88 [7]

Approximatley 4.39. If thought of like .33X=1.45, then you just divide 1.45 by .33

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3 years ago

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slavikrds [6]

A..... (im pretty sure)

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3 years ago

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Answer:

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Step-by-step explanation:

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2 years ago

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28.)Find the value of x.320(3x-10°A.) x = 22.67B.) x = 34.67C.) x = 21.6D.) x = 24.25

katen-ka-za [31]

Since the big triangle is an isosceles one, we conclude that the angles of the left triangle are: 32, 90 and 3x-10. Sinche the sum of this angles have to be 180° we have:

$(3x-10)+32+90=180$

Solving for x, we have:

$\begin{gathered} (3x-10)+32+90=180 \\ 3x-10+32+90=180 \\ 3x=180+10-90-32 \\ 3x=68 \\ x=\frac{68}{3} \\ x=22.67 \end{gathered}$

Therefore, x=22.67 and the answer is A.

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1 year ago

Evaluate the expression 6.2 - (-9.1).​

Evaluate the expression 6.2 - (-9.1).