Wednesday, 1 June 2011

TRIGONOMETRY ANGLE QUESTIONS WITH ANSWERS

Trigonometry questions related to angles in standard position, coterminal angles, complementary and supplementary angles, as well conversion from degrees to radians and vice versa, are presented. The solutions and answers are provided.


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Questions 1:

Graph - 435o in standard position.

Solution to Question 1:
  • Start from the initial side on the horizontal axis, positive direction, rotate 435 degrees in the negative direction to locate the terminal side which is in quadrant four. It helps to note that 435 degrees = 360 degrees + 75 degrees

    angle - 435<sup>o</sup> in standard position.
Questions 2:

Graph 9 Pi / 4 in standard position.

Solution to Question 2:
  • Start from the initial side on the horizontal axis, positive direction, rotate 9 Pi / 4 (radians) in the positive direction to locate the terminal side which is in quadrant one. Note that 9 Pi / 4 = 2 Pi + Pi / 4.

    angle 9 Pi / 4 in standard position.
Questions 3:

In which quadrant is the terminal side of an angle of - 3 Pi / 4 located?

Solution to Question 3:
  • The terminal side of - 3 Pi / 4 is located in quadrant three.

Questions 4:

In which quadrant is the terminal side of an angle of 750o located?

Solution to Question 4:
  • 750 degrees = 360 degrees + 360 degrees + 30 degrees. Hence an angle of 750 degrees, in standard position, has its terminal side in quadrant one.

Questions 5:

Find a coterminal angle t to angle - 27 Pi / 12 such that 0 <= t < 2 Pi.

Solution to Question 5:
  • We first note that - 27 Pi / 12 = -24 Pi / 12 - 3 Pi / 4 = - 2 Pi - 3 Pi / 4. A coterminal angle is obtained by adding or subtracting a whole number of 2 Pi (or 360 degrees). Hence a positive coterminal angle to - 27 Pi / 12 may be obtained by adding 2 (2 Pi) = 4 Pi.

    t = - 27 Pi / 12 + 4 Pi = 7 Pi / 4

  • Note that t is positive and smaller than 2 Pi..
Questions 6:

Find an angle t that is coterminal to 560o such that 0 <= t < 360o.

Solution to Question 6:
  • Note that 560 degrees = 360 degrees + 200 degrees which is greater than 360 degrees. So to obtain a coterminal angle smaller than 360 degrees we need to subtract 360 degrees from 560 degrees.

    t = 560 degrees - 360 degrees = 200 degrees.
Questions 7:

Determine the complementary angle t to Pi / 12.

Solution to Question 7:
  • The complementary angle to Pi / 12 is obtained as follows

    t = Pi / 2 - Pi / 12 = 5 Pi / 12
Questions 8:

Determine the complementary angle t to 34o.

Solution to Question 8:
  • The complementary angle t to 34 degrees is given by

    t = 90 degrees - 34 degrees = 56 degrees.
Questions 9:

Determine the supplementary angle t to 96o.

Solution to Question 9:
  • The supplementary angle t to 96 degrees is give by

    t = 180 degrees - 96 degrees = 84 degrees.
Questions 10:

Convert 75o to radians .

Solution to Question 10:
  • To convert from degrees to radians, we multiply by Pi and divide by 180. Hence 75 degrees in radians is given by

    75 * Pi / 180 = 5 Pi / 12 = 1.31 (rounded to 2 decimal places)
Questions 11:

Convert 7 Pi / 4 to degrees .

Solution to Question 11:
  • To convert from radians to degrees, we multiply by 180 and divide by Pi. Hence 7 Pi / 4 in degrees is given by

    (7 Pi / 4) * 180 / Pi

  • which simplifies to

    = 315 degrees.
Questions 12:

Convert 1.5 radians to degrees.

Solution to Question 12:
  • 1.5 radians into degrees is given by

    1.5 * 180 / Pi = 85.94 degrees (rounded to 2 decimal places)
Questions 13:

Convert 61o 05' 12" to degrees in decimal form.

Solution to Question 13:
  • An angle of 61 degrees 5 minutes and 12 seconds in decimal form is given by

    61 + 5 / 60 + 12 / 3600 = 61.07 (rounded to 2 decimal places).
Questions 14:

A central angle t of a circle with radius 2 meters subtends an arc of length 1.5 meters. Find angle t in degrees.

Solution to Question 14:
  • The use of the arc length formula s = r t where t is the angle (in radians) that subtends an arc of length s gives

    1.5 = 2 t

  • Solve for t to obtain

    t = 1.5 / 2 = 0.75 (radians)

  • We now convert t in degrees

    t = 0.75 * 180 / Pi = 42.97 degrees (rounded to 2 decimal places)

MY ROOMATE, SPHA

Ah guys there is this guy who is my roomate his name is Spha, hlikes mathematics very much he even count to infinity, when he is sleeping he use to say "calculate the mean without using a calculator" *loughin*

STORY ABOUT INFINITY

A very large mathematical convention was held in Las Vegas. The conventioneers filled two hotels, each with an infinite number of rooms. The hotels were across the street from each other and were owned by brothers. One evening, while everyone was out at a bar-b-que, one of the hotels burned to the ground. The brothers got together and worked out a plan. In the remaining hotel, they moved all guests to twice their room number -- room 101 moved to 202, room 1234 moved to room 2468, etc. Then all the odd number rooms were empty, and there were an infinite number of odd rooms. So the guests from the other hotel moved into them.

MY ROOM MATES @KGB

Yha guys Ncedo Madikane is staying at KGB res @wsu with his 3+2 roomates. To make sure u r a human being how many people stayin with ncedo, including him?

Youth Day on 16 June

Youth Day on 16 June in South Africa commemorates the start of the Soweto riots of 1976, initially sparked by a government edict that all instruction in black schools would be held in Afrikaans. The iconic picture of Hector Pieterson, a black schoolchild shot by the police, brought home to many people within and outside South Africa the brutalities of the Apartheid regime. The mascot for the 2010 FIFA World Cup, Zakumi, has his birthday on that day in 1994.

Youth Day on 16 June

Youth Day on 16 June in South Africa commemorates the start of the Soweto riots of 1976, initially sparked by a government edict that all instruction in black schools would be held in Afrikaans. The iconic picture of Hector Pieterson, a black schoolchild shot by the police, brought home to many people within and outside South Africa the brutalities of the Apartheid regime. The mascot for the 2010 FIFA World Cup, Zakumi, has his birthday on that day in 1994.