qu_08

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course Mth 164

Question: `q001. Note that there are four questions in this Assignment.

In general the sine and cosine functions and tangent function are defined for a circle of radius r centered at the origin. At angular position theta we have sin(theta) = y / r, cos(theta) = x / r and tan(theta) = y / x. Using the Pythagorean Theorem show that sin^2(theta) + cos^2(theta) = 1.

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Your solution:

sin^2(theta) + cos^2(theta) = 1

(y / r)^2 + (x / r)^2

(y^2 + x^2)/(r^2) = 1

r^2/r^2 = 1

confidence rating #$&*:2

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Given Solution:

`aThe Pythagorean Theorem applies to any point (x,y) on the unit circle, where we can construct a right triangle with horizontal and vertical legs x and y and hypotenuse equal to the radius r of the circle. Thus by the Pythagorean Theorem we have x^2 + y^2 = r^2.

Now since sin(theta) = y/r and cos(theta) = x/r, we have

sin^2(theta) + cos^2(theta) = (y/r)^2 + (x/r)^2 =

y^2/r^2 + x^2/r^2 =

(y^2 + x^2) / r^2 =

r^2 / r^2 = 1.

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Question: `q002. Using the fact that sin^2(theta) + cos^2(theta) = 1, prove that tan^2(theta) + 1 = sec^2(theta).

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Your solution:

tan^2(theta) + 1 = sec^2(theta)

sin^2(theta)/cos^2(theta) + 1 = 1 / cos^2(theta)

sin^2(theta)/cos^2(theta) * cos^2(theta)+ 1 * cos^2(theta)= 1 / cos^2(theta) * cos^2(theta)

sin^2(theta) + cos^2(theta) = 1

confidence rating #$&*:3

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Given Solution:

`aStarting with tan^2(theta) + 1 = sec^2(theta) we first rewrite everything in terms of sines and cosines. We know that tan(theta) = sin(theta)/cos(theta) and sec(theta) = 1 / cos(theta). So we have

sin^2(theta)/cos^2(theta) + 1 = 1 / cos^2(theta).

If we now simplify the equation, multiplying both sides by the common denominator cos^2(theta), we get

sin^2(theta)/cos^2(theta) * cos^2(theta)+ 1 * cos^2(theta)= 1 / cos^2(theta) * cos^2(theta).

We easily simplify this to get

sin^2(theta) + cos^2(theta) = 1,

which is thus seen to be equivalent to the original equation tan^2(theta) + 1 = sec^2(theta).

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Question: `q003. Prove that csc^2(theta) - cot^2(theta) = 1.

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Your solution:

csc^2(theta) - cot^2(theta) = 1

1/sin^2(theta) - cos^2/sin^2(theta) =

1 - cos^2(theta) = sin^2(theta)

sin^2(theta) + cos^2(theta) = 1

confidence rating #$&*:

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Given Solution:

`aRewriting in terms of sines and cosines we get

1 / sin^2(theta) - cos^2(theta)/sin^2(theta) = 1.

We now multiply through by the common denominator sin^2(theta) to get

1 / sin^2(theta) * sin^2(theta) - cos^2(theta)/sin^2(theta) * sin^2(theta) = 1 * sin^2(theta), or

1 - cos^2(theta) = sin^2(theta).

This is easily rearranged to give us sin^2(theta) + cos^2(theta) = 1, which we know to be true. The original equation is thus equivalent to this true equation, and is therefore true.

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Self-critique (if necessary):

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Self-critique Rating:3

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Question: `q004. Prove that sec^2(theta) * csc^2(theta) - csc^2(theta) = sec^2(theta).

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Your solution:

sec^2(theta)csc^2(theta) - csc^2(theta) = sec^2(theta)

1/cos^2(theta)1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta)

sin^2(theta)cos^2(theta)1/cos^2(theta)1 / sin^2(theta) - sin^2(theta)cos^2(theta)1/sin^2(theta) = sin^2(theta)* cos^2(theta)1/cos^2(theta)

1 - cos^2(theta) = sin^2(theta)

sin^2(theta) + cos^2(theta) = 1

confidence rating #$&*:2

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Given Solution:

`aRewriting in terms of sines and cosines we get

1/cos^2(theta) * 1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta).

We now multiply through by the common denominator sin^2(theta)* cos^2(theta) to get

sin^2(theta)* cos^2(theta) * 1/cos^2(theta) * 1 / sin^2(theta) - sin^2(theta)* cos^2(theta) * 1/sin^2(theta) = sin^2(theta)* cos^2(theta) * 1/cos^2(theta).

Simplifying we get

1 - cos^2(theta) = sin^2(theta), which we rearrange to get

sin^2(theta) + cos^2(theta) = 1.

Note that there are other strategies for proving identities, which you will see in your text.

Complete Assignment 8, including Class Notes, text problems and Web-based problems as specified on the Assts page.

When you have completed the entire assignment run the Query program. Submit SEND files from Query and q_a_.

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Self-critique (if necessary):

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Self-critique rating:

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Question: `q004. Prove that sec^2(theta) * csc^2(theta) - csc^2(theta) = sec^2(theta).

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Your solution:

sec^2(theta)csc^2(theta) - csc^2(theta) = sec^2(theta)

1/cos^2(theta)1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta)

sin^2(theta)cos^2(theta)1/cos^2(theta)1 / sin^2(theta) - sin^2(theta)cos^2(theta)1/sin^2(theta) = sin^2(theta)* cos^2(theta)1/cos^2(theta)

1 - cos^2(theta) = sin^2(theta)

sin^2(theta) + cos^2(theta) = 1

confidence rating #$&*:2

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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Given Solution:

`aRewriting in terms of sines and cosines we get

1/cos^2(theta) * 1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta).

We now multiply through by the common denominator sin^2(theta)* cos^2(theta) to get

sin^2(theta)* cos^2(theta) * 1/cos^2(theta) * 1 / sin^2(theta) - sin^2(theta)* cos^2(theta) * 1/sin^2(theta) = sin^2(theta)* cos^2(theta) * 1/cos^2(theta).

Simplifying we get

1 - cos^2(theta) = sin^2(theta), which we rearrange to get

sin^2(theta) + cos^2(theta) = 1.

Note that there are other strategies for proving identities, which you will see in your text.

Complete Assignment 8, including Class Notes, text problems and Web-based problems as specified on the Assts page.

When you have completed the entire assignment run the Query program. Submit SEND files from Query and q_a_.

"

Self-critique (if necessary):

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Self-critique rating:

#*&!

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Question: `q004. Prove that sec^2(theta) * csc^2(theta) - csc^2(theta) = sec^2(theta).

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Your solution:

sec^2(theta)csc^2(theta) - csc^2(theta) = sec^2(theta)

1/cos^2(theta)1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta)

sin^2(theta)cos^2(theta)1/cos^2(theta)1 / sin^2(theta) - sin^2(theta)cos^2(theta)1/sin^2(theta) = sin^2(theta)* cos^2(theta)1/cos^2(theta)

1 - cos^2(theta) = sin^2(theta)

sin^2(theta) + cos^2(theta) = 1

confidence rating #$&*:2

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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Given Solution:

`aRewriting in terms of sines and cosines we get

1/cos^2(theta) * 1 / sin^2(theta) - 1/sin^2(theta) = 1/cos^2(theta).

We now multiply through by the common denominator sin^2(theta)* cos^2(theta) to get

sin^2(theta)* cos^2(theta) * 1/cos^2(theta) * 1 / sin^2(theta) - sin^2(theta)* cos^2(theta) * 1/sin^2(theta) = sin^2(theta)* cos^2(theta) * 1/cos^2(theta).

Simplifying we get

1 - cos^2(theta) = sin^2(theta), which we rearrange to get

sin^2(theta) + cos^2(theta) = 1.

Note that there are other strategies for proving identities, which you will see in your text.

Complete Assignment 8, including Class Notes, text problems and Web-based problems as specified on the Assts page.

When you have completed the entire assignment run the Query program. Submit SEND files from Query and q_a_.

"

Self-critique (if necessary):

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Self-critique rating:

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