I need help with these questions

[prime dew]

1st one you get $\frac{\cos(t)(\sin(t)-1)+\cos(t)(\sin(t)+1)}{(\cos(t)-1)(\cos(t)+1)}$ which you then expand and simplify

[obtuse cipher]

mid.

[prime dew]

second one you Binomially expand:
1/cosy = secy
sec²y+2secytany+tan²y
2secytany = 2/cosy × siny/cosy
2siny/cos²y
all have denominators of cos²y now
(1+2siny+sin²y)/cos²y

which is just (1+siny)²/cos²y
to which we rationalise our denominator on the RHS
(1+siny)(1+siny)/(1+siny)(1-siny)

(1+siny)²/(1-sin²y) = (1+siny)²/(cos²y)

[chilly niche]

first question

[chilly niche]

second question

[prime dew]

um

[chilly niche]

for this one I think the question is wrong

forgot to mention it

[prime dew]

no

the question is correct

sin²t-1≠cos²t

other way around, that's where you dropped the minus

sin²t-1=-cos²t

@chilly niche

[chilly niche]

oh yes mb

[prime dew]

dw

[supple hollow]

wait i’m confused

i’m kinda lost at what i’m looking at i’m so sorry

You’re supposed to fully expand it and then simply the solution?