Question

i want to verify sin^4x - cos^4x = sin^2x - cos^2x. HOW DO YOU DO THAT? help me!!!!!

Answer 1

(sin² x )² - ( cos²x)² = ....

Answer 2

.....im lost><

Answer 3

You don't know the formula:
a² - b² = ...?

Answer 4

c

Answer 5

!!! :'(
a² - b² = ( a - b) ( a + b)
Here a = sin²x , b = cos²x
Now your turn to plug them in!

Answer 6

(sin² x )² - ( cos²x)² =sin²- cos²x !!!

Answer 7

Match them up, will you!!!
a² - b² = ( a - b) ( a + b)
(sin² x )² - ( cos²x)² = sin²- cos²x

Answer 8

(sin² x )² - ( cos²x)² =(sin²- cos²x) (sin² + cos²x)

Answer 9

There you go!
(sin² + cos²x) = .....?

Answer 10

(sin² x )² - ( cos²x)²

Answer 11

You need to do whatever to know this formula, check your text, notes ...
sin²x + cos²x =

Answer 12

1!!!

Answer 13

Finally (Sighs...)

Answer 14

Ahhh now i got it! Thank you so muchhh!!! you saved me.

Answer 15

trig is so hard...thank you!!

Answer 16

Here, there are 2 BASIC formulas, just 1 of them is trig. and so easily to remember :/