integral of sin(-4x)
Before performing the integration, let's calculate: sin(-4x)
ⓘ sin is odd, sin(-x) = -sin(x): sin(-4x) = -sin(4x)
-sin(4x)
Let's compute the integral: ∫(-sin(4x))dx
To use the known integral of sin(u), let u = 4x. Then du = 4dx, so dx = 14·du
We use ∫sin(u)du = -cos(u), then substitute u = 4x back
ⓘ The derivative of -(-cos(4x)4) is -sin(4x), so -(-cos(4x)4) is an antiderivative of -sin(4x): ∫(-sin(4x))dx = -(-cos(4x)4)
-(-cos(4x)4)
ⓘ Two minus signs cancel out: -(-cos(4x)4) = cos(4x)4
cos(4x)4
▶Indefinite integrals are defined up to an additive constant C, so this yields: cos(4x)4 + C