8. Introduction to Trigonometry
hard

$\left[\frac{\sin ^{2} 22^{\circ}+\sin ^{2} 68^{\circ}}{\cos ^{2} 22^{\circ}+\cos ^{2} 68^{\circ}}+\sin ^{2} 63^{\circ}+\cos 63^{\circ} \sin 27^{\circ}\right]$ નું મૂલ્ય ............ છે.

A

$3$

B

$1$

C

$2$

D

$0$

Solution

Given expression, $\frac{\sin ^{2} 22^{\circ}+\sin ^{2} 68^{\circ}}{\cos ^{2} 22^{\circ}+\cos ^{2} 68^{\circ}}+\sin ^{2} 63^{\circ}+\cos 63^{\circ} \sin 27^{\circ}$

$=\frac{\sin ^{2} 22^{\circ}+\sin ^{2}\left(90^{\circ}-22^{\circ}\right)}{\cos ^{2}\left(90^{\circ}-68^{\circ}\right)+\cos ^{2} 68^{\circ}}+\sin ^{2} 63^{\circ}+\cos 63^{\circ} \sin \left(90^{\circ}-63^{\circ}\right)$

$=\frac{\sin ^{2} 22^{\circ}+\cos ^{2} 22^{\circ}}{\sin ^{2} 68^{\circ}+\cos ^{2} 68^{\circ}}+\sin ^{2} 63^{\circ}+\cos 63^{\circ} \cdot \cos 63^{\circ}\left[\begin{array}{l}\left.\because \sin \left(90^{\circ}-\theta\right)=\cos \theta\right] \\ \text { and } \left.\cos \left(90^{\circ}-\theta\right)=\sin \theta\right]\end{array}\right.$

$=\frac{1}{1}+\left(\sin ^{2} 63^{\circ}+\cos ^{2} 63^{\circ}\right)$ $\left[\because \sin ^{2} \theta+\cos ^{2} \theta=1\right]$

$=1+1=2$

Standard 10
Mathematics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.