Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
You are not logged in.
#1 2008-12-06 01:45:15
- ganesh
- Moderator
Offline
High Scohol Mathematics - Trignometry II
1. Using the formula sin(A-B) = sinAcosB - cosAsinB, find the value of sin 15°.
2. If
by using the formula
.
3. The measure of angle of depression of the bottom of a building on a level fround from the top of the tower is 60° . How far is the building from the tower?
4. A tower is 100/√3 meters high. Find the angle of elevation if the point of observation is 100 meters away from its foot.
5. As observed from the top of a light house, 100 meters high above sea level, the angle of depression of a ship, sailing directly towards it, changes from 30° to 45° . Determine the distance travelled by the ship during the period of observation.
Character is who you are when no one is looking.
#2 2008-12-06 06:42:58
- vichavicha
- Novice
Offline
Re: High Scohol Mathematics - Trignometry II
Q3. Half the height of the tower.
Q5. 50 meters.
#3 2008-12-06 15:31:37
- ganesh
- Moderator
Offline
Re: High Scohol Mathematics - Trignometry II
OOps! I am sorry, I forgot to mention in #3 that the tower is 50 meters high.
Regarding your solution to #5, the solution isn't right.
I shall wait for any other membet to attempt, else I shall post all the solutions (sans diagams 
)
Character is who you are when no one is looking.
#4 2009-09-04 07:04:11
- rzaidan
- Full Member
Offline
Re: High Scohol Mathematics - Trignometry II
Hi ganesh
(1) sin(15°)=sin(45°-30°)=sin(45°)cos(30°)-cos(45°)sin(30°
1/√2)(√3/2)-(1/√2)(½)√3-1)/2√2
salam
#5 2009-09-07 00:06:40
- Fruityloop
- Full Member
Offline
Re: High Scohol Mathematics - Trignometry II
#3. 28.86751346 meters.
#4. 30°
#5. 73.2050808 meters.
Help slow global warming. Drive a prius.
July 2012 was the hottest month ever for the U.S.