UGC NET CSE | Junet 2015 | Part 3 | Question: 14

Question

Consider a triangle A(0,0), B(1, 1) and C(5, 2). The triangle has to be rotated by an angle of 45$^o$ about the point P(-1, -1). What shall be the coordinates of new triangle?

• A. $A' = (1, \sqrt{2}-1), B'(-1, 2\sqrt{2}-1) \text{ and }  C'=\bigl(3 \sqrt{2} -1, \frac{9}{2} \sqrt{2}-1 \bigr)$
• B. $A' = (1, \sqrt{2}-1), B'(2\sqrt{2}-1, -1) \text{ and } C'=\bigl(3 \sqrt{2} -1, \frac{9}{2} \sqrt{2}-1 \bigr)$
• C. $A' = (-1, \sqrt{2}-1), B'(-1, 2\sqrt{2}-1) \text{ and } C'=\bigl(3 \sqrt{2} -1, \frac{9}{2} \sqrt{2}-1 \bigr)$
• D. $A' = (\sqrt{2}-1,-1) B'(-1, 2\sqrt{2}-1) \text{ and } C'=\bigl(3 \sqrt{2} -1, \frac{9}{2} \sqrt{2}-1 \bigr)$

Answer 1

ans is C with some correction C' should be (3√2/2-1,9√2/2-1)

Comments

From which subject this question is? From where to practie such questions? Please tell the book name or online resource.

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subject :-,computer graphics (not meant for GATE exam though)

prefered book : schaum series

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How do we know if this is clockwise or anticlockwise? and please share the resource from where you spotted this question and answer.

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By default it is anticlockwise.  book is schaum series