Thursday, July 22, 2010
Trigonometry problems
Look for an example of trigonometry problem below.
If the distance of John standing from a wall is 100 m and the angle subtended by the top of the wall with the ground is 30o, measure the height of the wall in meters?
Solution:
* AB = distance of the man from the wall = 100 m
* BC = height of the wall = h (which has to be calculated)
* The trigonometric function that uses AB and BC is tan A , where A = 30o.
So tan 30o = BC / AB = h / 100
Therefore height of the wall h = 100 tan 30o = (100) 1/√3 = 57.74 m.
Lets work on coterminal angles in our next post....Guys practice many more such problems...
Tuesday, July 13, 2010
Trigonometry functions
Today when i was thinking what to start up, trigonometry functions struck to my mind. I decided to write on it, so here i am with it.
Trigonometry functions are also called as circular functions. They are functions of the angles. They are normally used to relate the angles of the triangle to the sides of the triangle. All trignometry terms are related to trigonometric functions. The basic trigonometric functions are Sine, Cosine and tangent, cot sec, cosec functions of a triangle. With all this it make us easy to find the sides of the triangle. Now let me give you the introduction of trigonometric identities.
Brief introduction of trigonometric identities:- Trigonometric identities are basically formed as the equalities is involve trigonometric functions and they prove to be true for every single value of the occurring. An identity is a basic equation that represents true for all of the possible values of its variables. Trigonometric identities are important; they involve the sums or differences of trigonometric angles.
We will solve these problems in my next post. Wait until then. But you will have to post your comment on this first.
Friday, July 9, 2010
Some problems on Trigonometry
Look for some trigonometry worksheets and work on them, to increase your knowledge. I have a few solved problem that will help you. Introduction to trigonometry is already given to you in my previous post, check that as well. Look below for some solved trigonometry problems.
Problem No1.
Let’s assume that the distance of a person from a tower is 100 m and the angle subtended by the top of the tower with the ground is 30o, now let’s calculate what the height of the tower in meters is? Below are the steps to solve the problem.
Steps:
- Draw a simple diagram to represent the problem. Label it carefully and clearly mark out the quantities that are given and those which have to be calculated. Denote the unknown dimension by say h if you are calculating height or by x if you are calculating distance.
- Identify which trigonometric function represents a ratio of the side about which information is given and the side whose dimensions we have to find out. Set up a trigonometric equation.
- Substitute the value of the trigonometric function and solve the equation for the unknown variable.
Solution:
- AB = distance of the man from the tower = 100 m
- BC = height of the tower = h (to be calculated)
- The trigonometric function that uses AB and BC is tan A, where A = 30o.
- So tan 30o = BC/AB=h/100
Therefore we conclude height of the tower h= 100 tan 30o = (100)/√3 =57.74m.
Problem No 2:-
Prove the given trig expression 1 + cot A/ 1 + tan A = 1 + cos A/ sin A + tan A
Solution:
Given
1 + cot A/ 1 + tan A = 1 + cos A/ sin A + tan A
Let us take L.H.S and we prove the R.H.S
L.H.S = 1 + cot A/ 1 + tan A
Here cot A = 1/ tan A
= 1 + (1/ tan A) / 1 + tan A
= (tan A + 1/ tan A) / 1 + tan A
= 1 + tan A/ (1 + tan A) tan A
L.H.S = cot A
R.H.S = 1 + cos A/ sin A + tan A
= 1 + cos A/ (sin A + (sin A/ cos A))
= 1 + cos A/ (sin A cos A + sin A/ cos A)
= 1 + cos A/ sin A(cos A + 1)/cos A
= (1 + cos A) cos A/ (cos A + 1) sin A
= cos A / sin A
R.H.S = cot A
Hence L.H.S = R.H.S
These problems will give you a clear idea on how to solve problems on trigonometry, but that is of no use until you don't work on it so what are you waiting for, start working on it immediately. Let me know how informative you found this post.
Wednesday, June 30, 2010
Introduction of Trigonometry
Introduction of Trigonometry:- Trigonometry is derived from the greek word which means "Study of a triangle" It gives us the relation between the angles. They are used to relate the angles and the length of a angle. It is used to solve problems on geometry and astronomy. With the help of trigonometry we find the height of a building.
The ratios of two sides of a triangle are taken. There are six possible combination. Each ratio is given a special name.
In this subject Greek letters are usually used.
(i) (Alpha) (ii) b (Beta) (iii) q (Theta)(iv) g (Gamma) (v) f (Phi) (vi) l (Lamda)
and so on to indicate the measure of an angle.Lets solve a problem of Trigonometry.
Problem No1:- Calculate the T-ratios of angle A and angle C from the given figure.
The trig function sine, it is written sin θ. We will learn on this more in my next post. Feel free to leave your comments.