PROVE that sin^4 x + cos^4 x= 1/4(3+cos4x). hence find the largest possible value and smallest possible value of sin^4 x+cos^4 x

Brainquicken

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- November 24th 2010, 12:02 AMJohnRameyTrigonometry QUESTION?
PROVE that sin^4 x + cos^4 x= 1/4(3+cos4x). hence find the largest possible value and smallest possible value of sin^4 x+cos^4 x

Brainquicken - November 24th 2010, 08:22 AMSoroban
Hello, John!

I'm delighted that you solved it.

Here's my approach . . .

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We have: .

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The maximum value of is 1.

The minimum value of is -1.

Therefore: .

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