Get the answers you need at Westonci.ca, where our expert community is dedicated to providing you with accurate information. Connect with professionals ready to provide precise answers to your questions on our comprehensive Q&A platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Prove that tan 225 cot 405 + cot 675 tan 765 = 0

Sagot :

[tex]tan225^ocot405^o+cot675^otan765^o=0\\\\L=tan(180^o+45^o)cot(2\times180^o+45^o)+\dots\\\dots+cot(4\times180-45^o)tan(4\times180^o+45^o)\\\\=tan45^ocot45^o+cot(-45^o)tan45^o=1-cot45^otan45^o\\\\=1-1=0\\\\===================================\\\\tan\alpha\times cot\alpha=1\\\\cot(-\alpha)=-cot\alpha[/tex]
[tex]tan 225^0 cot 405^0 + cot 675^0 tan 765^0=\\=tan(180^0+45^0)\cdot cot(2\cdot180^0+45^0)+\\+cot(4\cdot180^0-45^0)\cdot tan(4\cdot180^0+45^0)=\\=tan45^0\cdot cot45^0-cot45^0\cdot tan45^0=1\cdot1-1\cdot1=1-1=0[/tex]