SOLUTION: how to use 'sin','cosin' and 'tangent'in triangles.

Question 11857: how to use 'sin','cosin' and 'tangent'in triangles.
Answer by longjonsilver(2297) (Show Source): You can put this solution on YOUR website!
draw a right-angled triangle... a horizontal line AB and a vertical line BC at the right-end of the horizontal line. The hypotenuse is AC.

Now, draw another vertical line DE where D is some point on line AB...your choice and E is the other end of the line, somewhere on AC. OK so far?

Right, the angle A is whatever angle it is. The "interesting" or at least useful property is that the ratio of the sides in triangles ABC and ADE are the same... so AB/AC is the same as AD/AE etc.

So, we can use this fact that ratios of sides for a given angle are the same. Now there are 3 possible combinations of sides (well 6 actually). These are:

opposite/adjacent
adjacent/opposite

opposite/hypotenuse
hypotenuse/opposite

adjacent/hypotenuse
hypotenuse/adjacent

and these ratios have names:

opposite/adjacent --> tangent
adjacent/opposite --> cotangent

opposite/hypotenuse --> sine
hypotenuse/opposite --> cosecant

adjacent/hypotenuse --> cosine
hypotenuse/adjacent --> secant

For basic trig, you will use SIN, COS and TAN, the 3 "basic" ratios.

jon.

RELATED QUESTIONS
Use the following ratios to address the questions below: a. sin = 1/2 b. sin = 6/13... (answered by AnlytcPhil)

I NEED TO FIND AN ALGORYTHEM TO CALCULATE THE DISTANCE USING DEGREES, MINUTES, SECONDS... (answered by Alan3354,stanbon)

I'm trying to use the sum and differences identities to write this expression as a sine,... (answered by Alan3354)

Develop the formula for the tangent of the sum of angles in terms of the tangent of the... (answered by Fermat)

Develop the formula for the tangent of the sum of angles in terms of the tangent of the... (answered by venugopalramana)

How to draw a triangle diagram in kinematics and how to use cos and sin rule (answered by solver91311)

Find lengths correct to the nearest integer. There is an equalaterial triangle and it... (answered by ankor@dixie-net.com)

Use the unit circle and your knowledge of special triangles to find exact values for sin... (answered by ikleyn)

Use the given information to determine the values of sine 2 theta, cosine 2... (answered by ikleyn)