The value of sin22° + sin24° + sin26° + ........ + sin290° is?
A. 23
B. 0
C. 44
D. 22
Answer: Option A
Solution(By Examveda Team)
$$\eqalign{ & {\text{According to the question,}} \cr & {\sin ^2}{2^ \circ } + {\sin ^2}{4^ \circ } + {\sin ^2}{6^ \circ } + ..... + {\sin ^2}{90^ \circ } \cr & {\text{Number of terms}} \cr & = \frac{{l - a}}{d} + 1 \cr & = \frac{{90 - 2}}{2} + 1 \cr & = 45 \cr & {\text{But }}{\sin ^2}{90^ \circ } = 1 \cr & {\text{So, 22 pairs}} + {\sin ^2}{90^ \circ } \cr & = 22 + 1 \cr & = 23 \cr} $$Related Questions on Trigonometry
A. x = -y
B. x > y
C. x = y
D. x < y
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