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3 years ago

11

Maria cannot remember what she scored on the second test, but she knows that the sum of the three tests is 270. Write and solve

and addition equation to determine what she scored on her second test.
First Test: 92
Second Test : x
Third Test: 88

1 answer:

kati45 [8]3 years ago

4 0

88x+92=+270 solve the inequality

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Please help me *30 points* (please don't comment unless its answer :

Irina-Kira [14]

Answer: it would be 1.578 times 10^-6125

Or 1.578 times 10^-1230

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3 years ago

Prove the trigonometric identity

Annette [7]

Answer:

Proved See below

Step-by-step explanation:

Man this one is a world of its own :D Just a quick question are you a fellow Add Math student in O levels i remember this question from back in the day :D Anyhow Lets get started

For this question we need to know the following identities:

$1+tan^{2}x=sec^2x\\\\1+cot^2x=cosec^2x\\\\sin^2x+cos^2x=1$

Lets solve the bottom most part first:

$1-\frac{1}{1-sec^2x} \\\\$

Take LCM

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

now break the LCM

$\frac{-1}{-tan^2x}+\frac{-tan^2x}{-tan^2x}\\\\\frac{1}{tan^2x}+1\\\\cot^2x+1$

because 1/tan = cot x

and furthermore,

$cot^2x+1\\cosec^2x$

now we solve the above part and replace the bottom most part that we solved with $cosec^2x$

$\frac{1}{1-\frac{1}{cosec^2x} } \\\\\frac{1}{1-sin^2x} \\\\\frac{1}{cos^2x}\\\\sec^2x$

Hence proved! :D

4 0

3 years ago

Given: 1; -5; -13 ; -23 ; ...<br><br> Derive a formula for the nth term in the pattern.

mylen [45]

Answer:

f(n) = -n^2 -3n +5

Step-by-step explanation:

Suppose the formula is ...

f(n) = an^2 +bn +c

Then we have ...

f(1) = 1 = a(1^2) +b(1) +c

f(2) = -5 = a(2^2) +b(2) +c

f(3) = -13 = a(3^2) +b(3) +c

__

Here's a way to solve these equations.

Subtract the first equation from the second:

-6 = 3a +b . . . . . 4th equation

Subtract the second equation from the third:

-8 = 5a +b . . . . . 5th equation

Subtract the fourth equation from the fifth:

-2 = 2a

a = -1

Then substituting into the 4th equation to find b, we have ...

-6 = 3(-1) +b

-3 = b

and ...

1 = -1 +(-3) +c . . . . . substituting "a" and "b" into the first equation

5 = c

The formula is ...

f(n) = -n^2 -3n +5

3 0

4 years ago

Find the opposite of the opposite of each integer. 9

maks197457 [2]

Hi!

The opposite of 9 is -9.

Hope this helps!

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3 years ago

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