(sin70 + cos20)(sec70 + cosec20) (tan70 – cot20)

 

Asked by amruta.p.1978 | 3rd Oct, 2018, 11:10: PM

Expert Answer:

begin mathsize 16px style left parenthesis sin 70 space plus space cos 20 right parenthesis left parenthesis sec 70 space plus space cosec 20 right parenthesis space left parenthesis tan 70 space – space cot 20 right parenthesis
equals space open square brackets sin 70 space plus space cos left parenthesis 90 space minus space 70 right parenthesis close square brackets open square brackets sin left parenthesis 90 minus space 20 right parenthesis plus space cosec 20 close square brackets open square brackets tan left parenthesis 90 space minus space 20 right parenthesis space minus space cot 20 close square brackets
equals space open parentheses sin 70 space plus space sin 70 close parentheses left parenthesis cosec 20 space plus space cosec 20 right parenthesis left parenthesis cot 20 space minus space cot 20 right parenthesis
equals 2 sin 70 space cross times 2 cosec 20 space cross times space 0
equals 0 end style

Answered by Yasmeen Khan | 4th Oct, 2018, 10:54: AM

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