## What is the formula of cos3x?

Prove the following identity: cos 3x = 4 cos^3x – 3cosx Here is what I did and where I’m stuck: cos 3x = cos (2x+x) = (cos 2x)(cos x) – (sin 2x)(sin x) = (2 cos^2x-1)(cos x) – [(2 sinx)(cosx)](sinx) I’m not sure how you distribute this..

## What is the value of 1 cos2x?

Thus,1-cos2x=2sin²x.

## What is the formula of 1 sin 2x?

1+sin2x = 1+2sinxcosx = sin^2x + cos^2x + 2sinxcosx = (sinx + cosx)^2 = an alternate way of expressing 1+sin2x -> if this is what you were looking for.

## What is the formula of 1 cos2x?

Cos2x is a double angle trigonometry that has the espansion of cos2x = cos^2(x) -sin^2(x) but you know that sin^2(x) + cos^2(x) = 1.

## What is the formula of 1 cos theta?

(Math | Trig | Identities)sin(theta) = a / ccsc(theta) = 1 / sin(theta) = c / acos(theta) = b / csec(theta) = 1 / cos(theta) = c / btan(theta) = sin(theta) / cos(theta) = a / bcot(theta) = 1/ tan(theta) = b / a

## What is the value of 1 Cos?

The Value of the Inverse Cos of -1 As you can see below, the cos-1 (1) is 270° or, in radian measure, 3Π/2 . ‘-1’ represents the minimum value of the cosine function ever gets and happens at Π and then again at 3Π ,at 5Π etc..