How to prove this trig identity? (1 Viewer)

[hsc3hard5me]

cos^4(x) + cos^2(x).sin^2(x) = cos^2(x)

It's a prove that question in the Cambridge textbook

 

[seventhroot]

LHS =

cos^4(x) + cos^2(x)*sin^2(x)

factorise cos^2 out

cos^2(x) [cos^2(x) + sin^2(x)]

= cos^2(x)

= RHS

 

[Elise8842]

~

 

[faisalabdul16]

cos^4(x) + cos^2(x).sin^2(x) = cos^2(x)

It's a prove that question in the Cambridge textbook

Must be 1a or something

<img src="http://latex.codecogs.com/gif.latex?cos^{4}x&space;&plus;&space;cos^{2}xsin^{2}x&space;=&space;\\&space;cos^{2}x(cos^{2}x&space;&plus;&space;sin^{2}x)=&space;\\&space;cos^{2}x&space;\\&space;$Bracket&space;=&space;1" title="cos^{4}x + cos^{2}xsin^{2}x = \\ cos^{2}x(cos^{2}x + sin^{2}x)= \\ cos^{2}x \\ $Bracket = 1" />

 

[seventhroot]

Must be 1a or something

dead lel

 

[faisalabdul16]

~

Unnecessary. All you had to do was factorise.

 

[zhertec]

Must be 1a or something

<img src="http://latex.codecogs.com/gif.latex?cos^{4}x&space;+&space;cos^{2}xsin^{2}x&space;=&space;\\&space;cos^{2}x(cos^{2}x&space;+&space;sin^{2}x)=&space;\\&space;cos^{2}x&space;\\&space;$Bracket&space;=&space;1" title="cos^{4}x + cos^{2}xsin^{2}x = \\ cos^{2}x(cos^{2}x + sin^{2}x)= \\ cos^{2}x \\ $Bracket = 1" />

I died laughing

Rep+

 

[enigma_1]

Must be 1a or something

<img src="http://latex.codecogs.com/gif.latex?cos^{4}x&space;+&space;cos^{2}xsin^{2}x&space;=&space;\\&space;cos^{2}x(cos^{2}x&space;+&space;sin^{2}x)=&space;\\&space;cos^{2}x&space;\\&space;$Bracket&space;=&space;1" title="cos^{4}x + cos^{2}xsin^{2}x = \\ cos^{2}x(cos^{2}x + sin^{2}x)= \\ cos^{2}x \\ $Bracket = 1" />

don't be mean :/

at least he's using Cambridge

struggling to believe OP goes to hurlstone but ok

 

[seventhroot]

don't be mean :/

at least he's using Cambridge

struggling to believe OP goes to hurlstone but ok

it's probably because too hsc3hard5me

 

[faisalabdul16]

don't be mean :/

at least he's using Cambridge

struggling to believe OP goes to hurlstone but ok

Come on, as if that wasn't funny. I cant stop laughing.


Sorry OP <3333

 

[seventhroot]

Come on, as if that wasn't funny. I cant stop laughing.


Sorry OP <3333

same lel; that rekt tho

I was waiting for a MIF comment from engima

 

[hsc3hard5me]

it's probably because too hsc3hard5me

maths is hard

anyways thanks guys, i don't know what went over me, was q11 for the record lel

 

[faisalabdul16]

maths is hard

anyways thanks guys, i don't know what went over me, was q1 for the record lel

ftfy

Jokes

are you being serious?

Also, maths becomes easy with practice. Dont worry or stress too much, once you pick up the hang of questions and understand them, you'll be fine.

 

[hsc3hard5me]

ftfy

Jokes

are you being serious?

 

[seventhroot]

that looks like fitzpatrick

 

[faisalabdul16]

Oh wow

that looks like fitzpatrick

Nah it's cambridge. It has that development thingy on it

 

[seventhroot]

Nah it's cambridge. It has that development thingy on it

oops; clearly blind/asian

 

[hsc3hard5me]

that looks like fitzpatrick

pls

 

[zhertec]

that looks like fitzpatrick

Nah, cambridge is the only math book with "development" section