`cosx-sinx=-1` – InterviewSolution

InterviewSolution

1.	`cosx-sinx=-1`
Answer» Correct Answer - `x=(2npi+(pi)/(2))orx=(2n-1)pi, "where "n in I` `cosx-sinx=-1` `rArr(1)/(sqrt(2))cosx-(1)/(sqrt(2))sinx=(-1)/(sqrt(2))` `"cos"(pi)/(4)cosx-"sin"(pi)/(4)sinx=-"cos"(pi)/(4)=cos(pi-(pi)/(4))` `rArrcos(x+(pi)/(4))="cos"(3pi)/(4)` `rArrx+(pi)/(4)=2npi+-(3pi)/(4)` `rArrx+(pi)/(4)=2npi+(3pi)/(4)orx+(pi)/(4)=2npi-(3pi)/(4)` `rArrx=2npi+(pi)/(2)orx=(2n-1)pi" where"n in I`.

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