by proving l.h.s=r.h.s
Trigonometric identities are trigonometric equations that are always true.
Unlike equations (or inequalities), identities are always true. It is, therefore, not possible to solve them to obtain values of the variable(s).
Neither trigonometry nor any other subject can be used to prove questions. It may be possible to answer questions but that is another matter,
sin^2 (feta) + cos^2 (feta) = 1 sin (feta) / cos (feta) = tan (feta)
You make them less complicated by using trigonometric relationships and identities, and then solve the less complicated questions.
Typically, the pre-requisite for calculus is algebra and trigonometry. These are usually universally required because you need these skills to actually do the mathematics of the calculus. There are a lot of identities in trigonometry that you will wish you could remember when you are working with calculus of trigonometric functions.
It means that you prove that an equation is true for ALL values of the variable or variables involved.
Yes. 'sin2x + cos2x = 1' is one of the most basic identities in trigonometry.
these are the identities i need sinΘcosΘ=cosΘ sec^4Θ-tan^4Θ=sec²Θcsc²Θ (1+sec²Θ)/(1-secΘ)=(cosΘ-1)/(cosΘ)
Sin2x + Cos2x=1, so Cos2x=1-Sin2x and Sin2x=1-Cos2x. Also Sin/Cos = Tan. Sec2x=1+Tan2x. Cot2x+1=Csc2x.
plane trigonometry spherical trigonometry