PROVing trigonometry indenties

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The discussion revolves around proving the trigonometric identity (tanx - cosecx)² - (cotx - secx)² = 2(cosecx - secx). The user initially attempts to simplify the left-hand side (LHS) but encounters difficulties, particularly with signs and operations. A fellow participant advises on the importance of using parentheses for clarity and points out a missed minus sign in the calculations. After correcting the mistake, the user successfully arrives at the correct answer. The exchange highlights the collaborative nature of solving complex trigonometric problems.
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Homework Statement


(tanx - cosecx)2 - (cotx - secx)2 = 2(cosecx - secx)

Homework Equations


tanx = sinx/cosx
cotx = 1/tanx = cosx/sinx
cosecx = 1/sinx
secx = 1/cosx

The Attempt at a Solution



LHS = (tanx-cosecx)(tanx-cosecx) - (cotx-secx)(cotx-secx)
= tan2x - tanxcosecx - tanxcosecx + cosec2x - cot2x + cotxsecx + cotxsecx
= sin2x/cos2x - (sinx/cosx)(1/sinx) - (sinx/cosx)(1/sinx) + 1/sin2x - cos2x/sin2x + (cosx/sinx)(1/cosx) + (cosx/sinx)(1/cosx) - (1/cos2x)
= sin2x/cos2x - 2sinx/sinxcosx + 1/sin2x - cos2x/sin2x + 2cosx/sinxcosx - 1/cos2x
= sin2x-1 / cos2x + 1 - cos2x / sin2x - 2sinx+2cosx/sinxcosx
= -1 + 1 - 2sinx+2cosx / sinxcosx
= 2sinx + 2cosx / sinxcosx

and I'm stucked
help thanks in advance :)
ps. if i post in the wrong place I am sry cos I am new :/
 
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ytx123 said:
LHS = (tanx-cosecx)(tanx-cosecx) - (cotx-secx)(cotx-secx)
= tan2x - tanxcosecx - tanxcosecx + cosec2x - cot2x + cotxsecx + cotxsecx
= sin2x/cos2x - (sinx/cosx)(1/sinx) - (sinx/cosx)(1/sinx) + 1/sin2x - cos2x/sin2x + (cosx/sinx)(1/cosx) + (cosx/sinx)(1/cosx) - (1/cos2x)
= sin2x/cos2x - 2sinx/sinxcosx + 1/sin2x - cos2x/sin2x + 2cosx/sinxcosx - 1/cos2x
= sin2x-1 / cos2x + 1 - cos2x / sin2x - 2sinx+2cosx/sinxcosx
= -1 + 1 - 2sinx+2cosx / sinxcosx
= 2sinx + 2cosx / sinxcosx

You need to use parentheses to clarify addition vs division to avoid making trivial mistakes. You missed a minus sign that's present in the part I bolded. With the correct signs in the last line, you can divide through to obtain the desired result.
 
oh! thanks for pointing out my mistake , I've got the answer already :D thanks
 
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