Answer:
cos3x+tan3x=0
⟹cos3x=−tan3x
⟹cos3x=−sin3xcos3x
⟹cos23x=−sin3x
⟹1−sin23x=−sin3x
⟹sin23x−sin3x−1=0
This is a quadratic equation in sin3x.
sin3x=−(−1)±(−1)2−4×1×(−1)−−−−−−−−−−−−−−−−−√2×1
sin3x=1±5–√2
If x takes real values, the upper sign must be rejected.
sin3x=1−5–√2
⟹3x=nπ+(−1)nsin−11−5–√2
⟹x=13[nπ+(−1)nsin−11−5–√2]
Step-by-step explanation:
Hope this kind of helps
