Question

what is the value of cosec² (140° + alpha) - cot² (40° - alpha )
a) √2
b) -1
c) 0
d) 1

Answer 1

Ans.

${cosec}^{2}(140 + \alpha ) - {cot}^{2}(40 - \alpha ) \\ = {cosec}^{2} (180 - (40 - \alpha )) - {cot}^{2} (40 - \alpha ) \\ = {cosec}^{2}(40 - \alpha ) -{cot}^{2}(40 - \alpha ) \\ = 1$

So, option (d) is right.

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