trig iden

[fast agate]

i started on the LHS

but i couldnt get there

[round cypress]

expand lhs

remember that sin^2 + cos^2 = 1

so -sin^2 - cos^2 = -1

[fast agate]

@round cypress

can you help me find my error please?

[round cypress]

there is no error

[fast agate]

i done these stuff at gcse further maths but cant do this one

[round cypress]

expand rhs if your stuck and see what u need to get to

[fast agate]

btw i got a questions

do you treat the LHS/RHS like an equation or expression

[round cypress]

wdym

[fast agate]

like you know when lets say you got
2x+1
and
2x+1 = 0

you can square the 2x+1=0 because its an equation but you cant do that to 2x+1 since its an expression

[round cypress]

oh right

[fast agate]

do you treat these types of equations as which one

[round cypress]

ur trying to prove something so you dont have an equation cuz u dont know if its true

[fast agate]

since idk what rules i can use

[round cypress]

so its an expression

[fast agate]

ah i see

[round cypress]

you just manipulate the sides

[fast agate]

identity since basically means expression

kinda got confused since its similar to =

[round cypress]

not really

identity mean its true for all x

[fast agate]

yea

[round cypress]

you can still move stuff around

if you know its true

[fast agate]

i see

a bit in the middle

[fast agate]

ah i gotcha pretty helpful that

thank you

just sub in cos2x+sin2x into 1

🙂

[round cypress]

yep

[fast agate]

appreciate it

[sage lodge]

i have a trig identities question. any help with this please

[round cypress]

factorise

[sage lodge]

so (cos2x)^2 - (sin2x)^2 for the numerator

[round cypress]

ehhh

yeah

factorise