Find cos(2x) from the given information. tan(x)= 9/8, x in quadrant I

cos2x=-17/145

Step-by-step explanation:

Recall cos2x=cos^2x-sin^2x

Or cos2x=cos^2x-(1-cos^2x)*

Or cos2x=2cos^2x-1**

*By a Pythagorean Identity

**Combined like terms

I'm going to use third identity from above because I only have to find cosx or cos^2x to get requested answer for cos2x.

Recall Pythagorean identity 1+tan^2x=sec^2x.

Plug in our tangent valuem...

1+(9/8)^2=sec^2x

1+81/64=sec^2x

145/64=sec^2x

Cosine and secant are reciprocals of each other.

64/145=cos^2x

Now we are ready to plug in and get final

cos2x=2cos^2x-1

cos2x=2(64/145)-1

cos2x=128/145-1

cos2x=-17/145

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