2sinx / cos3x = tan3x - tanx -verify the identity-

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

the inequality is:

250c+180g≥950

step-by-step explanation:

let c denotes the number of days in a week   miyoko worked as a cryptographer.

and g denotes the number of days in a week she works as a geologist.

now we are given that she earns $250 for every day she works as a cryptographer,and earns $180 for every day she works as a geologist.

now miyoko's goal is to earn more than $950 this week.

hence, the inequality could be represented as:

250c+180g≥950

a .4y4

hope this !