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3.Trigonometrical Ratios, Functions and Identities
easy
જો $\sin \theta + {\rm{cosec}}\theta = {\rm{2}}$, તો ${\sin ^2}\theta + {\rm{cose}}{{\rm{c}}^{\rm{2}}}\theta = $
A
$1$
B
$4$
C
$2$
D
એકપણ નહીં.
Solution
(c) ${\sin ^2}\theta + {\rm{cose}}{{\rm{c}}^2}\theta $
$= {(\sin \theta + {\rm{cosec}}\theta )^2} – 2\sin \theta {\rm{ cosec}}\theta $
$ = {(2)^2} – 2 = 4 – 2 = 2,$
since $(\sin \theta + {\rm{cosec}}\theta ) = 2.$
Standard 11
Mathematics