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Showing posts from February, 2010

### Proving trigo identities Part III

This question involves the use of rationalization to prove trigo identites

Rationalization is a commonly used technique in surds. Click here to check out how rationalization is used in surds.

Question 1

Whats Next?
Click here for Proving trigo identities Part IV

### Proving trigo identities Part II

Question 1

My friend came up with another way of proving the above identity

Question 2

What's Next?
Click here for Proving trigo identities Part III

### Proving trigo identities Part I

Strategy
Choose the more complicated side to start
Keep in mind what you are trying to prove

Question 1
Show that:

Solution:

Question 2
Show that

The more complicated side is LHS

What's Next?
Click here for Proving trigo identities Part II

### Trigo Equations Part IV

Equations that contain only sin x and cos x Strategy: Divide by cos x  to obtain tan x

This type of equation has to be solved using the R formula.

What's Next ?
Click here to learn how to trigo equations using the R formula
Click here to learn how to prove trigo identities

### Trigo Equations Part III

Factorization to obtain basic type

Question 1

Use of idenity followed by factorization

Question 2

Question 3

What's Next?
Click here for Trigo Equations Part IV

### R formula Part II

ABCD is a quadrilateral where AB = 2 cm and BC = 4cm. Angles BAD and BCD each equals to θ

a) Express the length of AD in terms of θ
b) Determine the maximum length of AD and the corresponding value of θ
c) Find the value of θ for which AD= 3cm

Worked solutions
a)

b)

c)

Given AD = 3 cm

What's Next?