Question
$3(\sin\text{x}-\cos\text{x})^4+6(\sin\text{x}+\cos\text{x})^2+4(\sin^6\text{x}+\cos^6\text{x})=$ _______.

Answer

$3(\sin\text{x}-\cos\text{x})^4+6(\sin\text{x}+\cos\text{x})^2+4(\sin^6\text{x}+\cos^6\text{x})=$ 13.
Solution:
Given expression is 
$3(\sin\text{x}-\cos\text{x})^4+6(\sin\text{x}+\cos\text{x})^2+4(\sin^6\text{x}+\cos^6\text{x})$
$$$=3[\sin^2\text{x}+\cos^2\text{x}-2\sin\text{x}\cos\text{x}]^2+6(\sin^2\text{x}+\cos^2\text{x}+2\sin\text{x}\cos\text{x})\\+4[(\sin^2\text{x})^3+(\cos^2\text{x})^3]$
$=3[1-2\sin\text{x}\cos\text{x}]^2+6(1+2\sin\text{x}\cos\text{x})+4[(\sin^2\text{x}+\cos^2\text{x})^3\\-3\sin^2\text{x}\cos^2\text{x}(\sin^2\text{x}+\cos^2\text{x})]$
$=3(1+4\sin^2\text{x}\cos^2\text{x}-4\sin\text{x}\cos\text{x})+6+12\sin\text{x}\cos\text{x}+4-12\sin^2\text{x}\cos^2\text{x}$
$=3+12\sin^2\text{x}\cos^2\text{x}-12\sin\text{x}\cos\text{x}+6+12\sin\text{x}\cos\text{x}+4-12\sin^2\text{x}\cos^2\text{x}$
$=3+6+4=13$
Hence, the value of the filler is $13$.$$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free