A) 4
B) 2
C) 1
D) ½
Correct Answer: B
Solution :
Given that, \[\cos A+{{\cos }^{2}}A=1\] \[\Rightarrow \] \[\cos A=1-{{\cos }^{2}}A={{\sin }^{2}}A\] ?(i) Now,\[2\,\,({{\sin }^{2}}A+{{\sin }^{4}}A)=2\,\,({{\sin }^{2}}A+{{\cos }^{2}}A)\][from Eq. (i)] \[=2\cdot (1)=2\]\[(\because {{\sin }^{2}}\theta +{{\cos }^{2}}\theta =1)\]You need to login to perform this action.
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