Wiskunde Multiple Choice Vraag uit Gricha's Wiskundige Vragenbank

cot (x + 45°) is gelijk aan	A. \(\boldsymbol{\frac {1\,-\,\tan x} {1\,+\,\tan x} }\)
	B. \(\boldsymbol{\frac {1\,+\,\tan x} {1\,-\,\tan x} }\)
	C. \(\boldsymbol{\frac {\tan x\,-\,1} {\tan x \,+\,1} }\)
	D. \(\boldsymbol{\cot\,(x-45^\circ) }\)
	E. \(\boldsymbol{-\cot x}\)

[ 5-6625 - op net sinds 20.8.12-(E)-4.11.2023 ]

Translation in E N G L I S H

cot (x + 45°) is equal to	A. \(\boldsymbol{\frac {1\,-\,\tan x} {1\,+\,\tan x} }\)
	B. \(\boldsymbol{\frac {1\,+\,\tan x} {1\,-\,\tan x} }\)
	C. \(\boldsymbol{\frac {\tan x\,-\,1} {\tan x \,+\,1} }\)
	D. \(\boldsymbol{\cot\,(x-45^\circ) }\)
	E. \(\boldsymbol{-\cot x}\)

Oplossing - Solution

$cot(x+45^{\circ})=\frac{1}{tan(x+45^{\circ})}=\frac{1}{\frac{tan\:45^{\circ}+tan\:x}{1-tan\:45^{\circ}.tan\:x}}=\frac{1}{\frac{1+tan\:x}{1-tan\:x}}=\cdots$

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