Practicing Success
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CUET Preparation Today
If cos42° + sin42° = k then what is the value of cos242° - sin242°. |
-k\(\sqrt {1-k}\) k\(\sqrt {2-k^2}\) k\(\sqrt {1-k}\) -k\(\sqrt {1+k}\) |
k\(\sqrt {2-k^2}\) |
cos242° - sin242° = (cos42° + sin42°)(cos42° - sin42°) = (k)(x) If cos + sin = k, than cos - sin = \(\sqrt {2-k^2}\) (Always) So, cos242° - sin242° = k\(\sqrt {2-k^2}\) |
