Question

Can someone help me figure out if this is an identity?

Answer 1

@tinybookworm

Answer 2

cos x + sin x tan x

= cos x + (sin x * sin x0 / cos x

= cos x + sin^2 x / cos x

= (cos^x + sin^2 x )/ cos x

Now sin^2 x + cos ^ 2 x = 1

so we have 1 /cos x = sec x

yes this is an identity

Answer 3

ok?

Answer 4

Thank you! Can you help me with one more?

Answer 5

let s = sin x and c = cos x

(c -s)^2 + ( c +s)^2

= c^2 + s^2 -cs + c^2 + s^2 + cs

but c^2 + s^2 = 1

so we have

1 - cs + 1 + cs = 2

Answer 6

ok?

Answer 7

Thank you so much! I understand now

Answer 8

yw