trig solving for x

[spiral storm]

How would i go about solving d? (Some hints) 😭

[twilit rapids]

You can start by simplifing 3sinªcosª

@spiral storm

[spiral storm]

I try quick

[twilit rapids]

Quick question: is ª in radians or in degrees?

I'm going to guess degrees

[spiral storm]

Degrees

Its high school math :v

[twilit rapids]

Gotcha

Just ping if u need another hint

[spiral storm]

When i simplify, do u mean chaning it into a double angle?

[twilit rapids]

No! But nice thought

[spiral storm]

Mmmm

[twilit rapids]

2sin(t)cos(t)=sin(2t)

So it can be rewritten as

3/2 x sin(2a)

[spiral storm]

Ok ok i see

[mortal iris]

double angle woudn't help in this situation

[spiral storm]

No double? What should i try then?

[mortal iris]

I'm thinking, not able to get the idea

[twilit rapids]

I will try to solve it myself

[spiral storm]

Pls

I'm a bit confused now

[mortal iris]

ok I got something

not sure if it's correct

but anyways

you see the last two terms?

simplify them

[spiral storm]

ok then?

so I just take out the 6 right

[mortal iris]

let's just keep sin alpha =x and cos alpha=y

[mortal iris]

yeah

3xy-y-2x+6x^2

y(3x-1)+2x(3x-1)=0

(3x-1)(y+2x)=0

so alpha is arcsin(1/3)

[spiral storm]

so what happpens to the -1 from 6x^2

I'm taking that from the simplification 6(x^2-1)

I might be confusing myself

[mortal iris]

you couldn;t take like that

if you do it's 6(x^2-1/3)

if you common fact a number from expression, when you multiply it again you should get the same experession

[spiral storm]

if u look at d) the expression is -6x^2+6 tho wouldnt taking 6 out make it -6(x^2-1)

[mortal iris]

no

actually 1-cos^2 (x)= sin^2 (x)

[spiral storm]

that is true I tried those variations but I could get to the answer

would u like to see the textbook answer?

[twilit rapids]

Yes

[spiral storm]

phone a bit slow :(

[twilit rapids]

Happens :)

[spiral storm]

a bit smudged

the one above ex10

I try n get better image

[hushed wadi]

another solution i found is tan alpha = 0

[spiral storm]

how did you go about getting tan alpha?

[hushed wadi]

try to factorize urself
$3\sin{\alpha}\cos{\alpha}+6\sin^2{\alpha}-2\sin{\alpha}-\cos{\alpha}$

[main brook]

Ɱιყυ

[hushed wadi]

also that 6 sin^2 alpha comes from -6(cos alpha)^2 + 6

[spiral storm]

I've tried I just cant get to your answer

[hushed wadi]

well sorry