Grade 12 trig: evaluate exactly: (tan8pi/9 - tan5pi/9) / (1 + tan8pi/9 x tan5pi/9)

[e12]

Question: Evaluate using exact values.
tan8pi/9 - tan5pi/9 ALL divided by 1 + tan8pi/9 x tan5pi/9

 

[mmm4444bot]

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[Dr.Peterson]

Question: Evaluate using exact values.
tan8pi/9 - tan5pi/9 ALL divided by 1 + tan8pi/9 x tan5pi/9

Have you learned the angle-sum identities? If so, this can be solved by recognizing one of them.

If not, you'd need something different. That's part of the reason we ask you to provide context for your questions.