Trigonometric Treasure 4 ! \rightarrow 4!

Algebra Level 4

If sin ( 7 x ) = cos ( 11 x ) \sin (7x) = \cos (11x) , what is tan ( 9 x ) + cot ( 9 x ) \tan (9x) + \cot (9x) ?


The answer is 2.

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1 solution

If, sin 7 x = cos 11 x \sin 7x = \cos 11x

Then, sin 7 x = sin ( 90 11 x ) \sin 7x = \sin (90 - 11x)

7 x = 90 11 x 7x = 90 - 11x

18 x = 90 18x = 90

x = 5 x=5

Substituting the value of x, we get

tan 9 ( 5 ) + cot 9 ( 5 ) \tan 9(5) + \cot 9(5)

tan 45 + cot 45 \tan 45 + \cot 45

1 + 1 1 + 1 = 2 2

N I C E S O L U T I O N \color{#3D99F6}{NICE SOLUTION}

Razing Thunder - 11 months, 1 week ago

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Nice problem too..

Shriniketan Ruppa - 11 months, 1 week ago

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