Question

The value of $si{n}^2{29}^{\circ }+si{n}^2{61}^{\circ }$ is

• A. $2si{n}^2{29}^{\circ }$
• B. 1
• C. 0
• D. $2co{s}^2{61}^{\circ }$

Answer 1

The correct option is B

1

$si{n}^2{29}^{\circ }+si{n}^2{61}^{\circ }=si{n}^2{29}^{\circ }+si{n}^2({90}^{\circ }-{29}^{\circ })(\because sin({90}^{\circ }-29)=cos61)=si{n}^2{29}^{\circ }+co{s}^2{29}^{\circ }(\because sin(90-\theta )=cos\theta )=1(\because si{n}^2\theta +co{s}^2\theta =1)$