here is the first one
continue more??
Hi! I needed help verifying the following proofs! If anyone wants to contribute by solving either of them, I will greatly appreciate it!
Sin^(4) x - cos^(4) x = 1-2cos^(2) x
and:
sec x - sin x • tan x = cos x
and:
{(cos^(2) x)/(1+ sin x)} -1= -sin x
thank you!