Check out some similar questions!

beckoning · Jul 14, 2009, 09:19 PM

Here are some questions I am having problems with in my trig/precalc class.

1. Find the coordinates, to the nearest hundreth, of the vertices of triangle PQR with P(0,1), Q(0,-4), and R(2,5) after a 45° rotation about the origin.

2. Find the value if sin A=12/13 with 90° ≤ A ≤ 180° and if sin B = -7/25 with -90° ≤ B ≤ 0°.
cos(A-B)

3. Two pilots take off from the same airport. Mason heads due south. Nancy heads 23° west of south. After 400 land miles, how far is Nancy from Mason's route?

4. Find the value if sin A=12/13 with 90° ≤ A ≤ 180° and if sin B = -7/25 with -90° ≤ B ≤ 0°.
sin(A+B)

5. Find the value if sin A=12/13 with 90° ≤ A ≤ 180° and if sin B = -7/25 with -90° ≤ B ≤ 0°.
tan(A+B)

6. Find the coordinates, to the nearest hundreth, of the vertices of triangle FGH with F(0,10) G(10,0) and H(1, -1) after a 75° rotation about the origin.

These are just a few questions, I have hundreds more that I am doing and having trouble with so if you're interested I can send you more.

Unknown008 · Jul 15, 2009, 11:25 AM

1. Have you tried with a sketch for 1.

2. For this, you need you trig basic trig identities,

$cos(A-B) = cosAcosB + sinAsinB$

To find cos A and cos B, make simple sketches. Cos A is equal to the adjacent side over the hypotenuse. You have the hypotenuse and the opposite side of angle A, you can find the adjacent through Pythagoras' Theorem. And the same logic for the second one.

3. Do a sketch! You'll require the cosine rule here...

$A^2 = B^2+C^2-2(B)(C)cos(a)$

4. The similar reasoning as for 2.

$sin(A+B) = cosAsinA + cosBsinB$

5. Same here

$tan(A+B) = \frac{tanA+tanB}{1-tanAtanB}$

6. Try doing this after the first one.

makeveli1 · Jul 22, 2009, 06:00 PM

What is 30% of 6,890,000?

makeveli1 · Jul 22, 2009, 06:06 PM

What is 30% 6,890,000

Unknown008 · Jul 23, 2009, 02:52 AM

No need to double post makeeveli1. You should have started a new thread for your question. I'll not do you work, but give you an example.

Percent means for each '100'. 1% means that there is one for each 100. 30% means that there is 30 for each 100. If you have 50% of something, it means that if you had to divide the 'thing' into 100 pieces, you would obtain 50 pieces.

Example:
$50%\, of\, 2,543,152 = \frac{50}{100} \times 2,543,152$

Greek2Me · Sep 25, 2009, 04:21 PM

Here's a couple of articles for those who don't want to memorize all the trig functions but desparately need to get through the class...

How to Pass That Trigonometry Exam (Without Losing Your MIND!) Part II - Unknown Angles | eHow.com

How to Pass That Trigonometry Exam (Without Losing Your MIND!) Part I - Unknown Sides | eHow.com