Now that we have derived cos2x = cos 2 x - sin 2 x, we will derive cos2x in terms of tan x. We will use a few trigonometric identities and trigonometric formulas such as cos2x = cos 2 x - sin 2 x, cos 2 x + sin 2 x = 1, and tan x = sin x/ cos x. We have, cos2x = cos 2 x - sin 2 x = (cos 2 x - sin 2 x)/1 = (cos 2 x - sin 2 x)/( cos 2 x + sin 2 x) [Because cos 2 x + sin 2 x = 1]. Divide the
Want to join the conversation?how is tan squared less 1 = secant? Each question for this section uses this central calculation to simplify the calculations, but it makes no logical senseWe must simplify tan^2 theta - 1 when we multiply cosx/2 in numerator and denominator,cotx/2=cos^2x/2/sinx/2*cosx/2By the formulas cos2x=2cos^2x-1 ==>cos^2x/2=1+cosx/2sin2x=2sinxcosx cotx/2=1+cosx/2/sinx/2=>cotx/2=1+cosx/sinxButton navigates to signup pageCan someone help me with establishing an identity? I'm having a bit of trouble with those types of navigates to signup pageComment on Calla Andrews's post “Can someone help me with ...”Basically, If you want to simplify trig equations you want to simplify into the simplest way possible. for example you can use the identities -cos^2 x + sin^2 x = 1sin x/cos x = tan xYou want to simplify an equation down so you can use one of the trig identities to simplify your answer even more. some other identities you will learn later include -cos x/sin x = cot x1 + tan^2 x = sec^2 x1 + cot^2 x = csc^2 xhope this helped!Comment on Ash_001's post “Basically, If you want to...”Find the value of cot25+cot55/tan25+tan55 + cot55+cot100/tan55+tan100 + cot100+cot25/tan100+tan25Button navigates to signup pageComment on Rajvir Saini's post “Find the value of cot25+c...”i'm too lazy to work this out, but here this helpsComment on Timber Lin's post “i'm too lazy to work this...”right, but how do you simplify more complex problems?Button navigates to signup pageButton navigates to signup page ancuTT. 433 29 26 61 166 410 350 122 224