Fint the value of Sin theta + Cos theta ?

If Sin theta * Cos theta=1/2 find the value of Sin theta + Cos theta

2 Answers
Swarna Islam
Mar 16, 2018

sqrt2

Explanation:

sinthetaxxcostheta=1/2

=>2sinthetacostheta=1

=>sin2theta=sin90^o
=>2theta=90^o
:.theta=45^o
sintheta+costheta=sin45^(o)+cos45^o=1/sqrt2+1/sqrt2=2/sqrt2=sqrt2(Ans.)

Sunayan S
Apr 29, 2018

Another approach...

Explanation:

Given:-

sintheta cdot costheta=1/2

=>2 cdot sintheta cdot costheta=1

"So,"

sintheta +costheta

=sqrt((sintheta+costheta)^2)

=sqrt(sin^2theta+2 cdot sintheta cdot costheta+cos^2theta

=sqrt((sin^2theta+cos^2theta)+2 cdot sintheta cdot costheta

=sqrt(1+1)

=sqrt2

Hope it helps...

Thank you...

:-)

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