Trigonometric Identities
Additional Trigonometric Identities
Review of Functions and Angles
Problem :
Prove the following identity:
tan(θ)cos(θ) = sin(θ)
= sin(θ)


Problem :
Prove the following identity:
(sin(θ))^{4} +2(sin(θ))^{2}(cos(θ))^{2} + (cos(θ))^{4} = tan(θ)cot(θ)
(sin(θ))^{4} +2(sin(θ))^{2}(cos(θ))^{2} + (cos(θ))^{4} = tan(θ)cot(θ)


(sin(θ))^{4} +2(sin(θ))^{2}(cos(θ))^{2} + (cos(θ))^{4} =


(sin(θ))^{4} +2(sin(θ))^{2}(cos(θ))^{2} + (cos(θ))^{4} = 1


((sin(θ))^{2} + (cos(θ))^{2})((sin(θ))^{2} + (cos(θ))^{2}) = 1


Problem :
Prove the following identity:
 cos(θ)(cot(θ))^{2} = cot(θ)sin(θ)
 cos(θ)(cot(θ))^{2} = cot(θ)sin(θ)


 = cos(θ)


 = 1


(csc(θ))^{2}  (cot(θ))^{2} = 1


(csc(θ))^{2} = 1 + (cot(θ))^{2}

