Question

Sin^4a+cos^4a kitna hoga iski value​

Answer 1

Answer:

$\frac{2-Sin^{2}2a}{2}$

Step-by-step explanation:

    $Sin^{4} a + Cos^{4}a$

⇒ $(Sin^{2} a)^{2}+(Cos^{2}a)^{2}$

We know that $a^{2} +b^{2} = (a+b)^{2} -2ab$

⇒ $(Sin^{2}a+Cos^{2}a)^{2}-2Sin^{2}aCos^{2}a$

We know that $Sin^{2} x+Cos^{2} x= 1$

⇒ $1^{2} - 2Sin^{2}aCos^{2}a$

Multiplying and dividing by $2$

⇒ $\frac{2-4Sin^{2}aCos^{2}a }{2}$

We know that $Sin2x = 2SinxCosx$

⇒ $\frac{2-Sin^{2}2a}{2}$