Need help rush on a Trigonometry assign brb 10mins?

Question

True or False
1 Tan^2x + 1 = Sec ^2x

2. 2 sin20ºsin5º = cos15º - cos25º

3. cos45º= cos(30º+15º)

4. Tan255º = 2 - √3

5. sin 25º = sin10ºcos15º + sin15ºcos10º

6.cosx/sinx = tanx

7. cos^2θ + sin^2θ = -1

8. cos74º= cos60ºcos14º + sin60ºsin14º

9. cos(5[pie]/12) = √6-√2/4

10. cos [pie]/3 = cos[pie]/12cos[pie]4 - sin[pie]/4


thanks for the one who will answer dis....

common guyz first person to answer correctly wins my 10 pts

10pts is still waitng

Answer 1

1.)
tan(x)^2 + 1 = sec(x)^2
(sin(x)/cos(x))^2 + 1 = (1/cos(x))^2
(cos(x)^2 + sin(x)^2)/(cos(x)^2) = (1/cos(x))^2
1/(cos(x)^2 = 1/cos(x)^2

True

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2.)
2sin(20)sin(5) = cos(15) - cos(25)
Using a calculator this is true.

3.)
cos(45) = cos(30 + 15)

True, just do to the fact that 30 + 15 = 45

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4.)
tan(255) = 2 - sqrt(3)
Using a calculator, False

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5.)
sin(25) = sin(10)cos(15) + sin(15)cos(10)

sin(10 + 15) = sin(10)cos(15) + sin(15)cos(10)

Just the rule for sin(x + y), this is True

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6.)
cos(x)/sin(x) = tan(x)

since sin(x)/cos(x) = tan(x)

cos(x)/sin(x) = cot(x) or 1/(tan(x))

This is False

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7.)
cos(x)^2 + sin(x)^2 = -1
(1 - sin(x)^2) + sin(x)^2 = -1
1 - sin(x)^2 + sin(x)^2 = -1
1 = -1

False

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8.)
cos(74) = cos(60)cos(14) + sin(60)sin(14)

using the rule cos(x + y) = cos(x)cos(y) - sin(x)sin(y)

This is False

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9.)
cos(5pi/12) = (sqrt(6) - sqrt(2))/4

cos((pi/4) + (pi/6)) =
cos(pi/4)cos(pi/6) - sin(pi/4)sin(pi/6) =
(sqrt(2)/2)(sqrt(3)/2) - (sqrt(2)/2)(1/2) =
(sqrt(6)/4) - (sqrt(2)/4) =
(sqrt(6) - sqrt(2))/4

ANS : True

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10.)
By this do you mean
cos(pi/3) = (cos(pi/12)cos(pi/4)) - sin(pi/4)
or
(cos(pi)/3) = (cos(pi)/12)(cos(pi)/4) - (sin(pi)/4)

sorry that i didn't answer the ones that i replied with using a calculator.

Answer 2

correct: 1, 2, 3, 5, 9
wrong: 4, 6, 7, 8, 10