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## Rosy95 2 years ago Please help on PreCal

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1. cgreenwade2000

Ok go

2. Rosy95

Find an expression equivalent to... |dw:1358280084977:dw|

3. cgreenwade2000

any expression? or is this something needing to involve a certain method? There's a number of ways to find an equivalent.

4. Rosy95

I am not sure. The answer choice are... A. sec^2 theta B. cot theta C. tan^2 theta D. cos^2 theta

5. cgreenwade2000

|dw:1358280261643:dw|

6. cgreenwade2000

|dw:1358280353086:dw|

7. cgreenwade2000

Oh, my pictures got cut off, but the math is easy to see if you know definitions of trig functions and basic algebra skills.

8. Rosy95

Yes I can see. Thanks for writing out the equations. So the answer would be A. sec^2 theta?

9. cgreenwade2000

|dw:1358280516292:dw|

10. Rosy95

So can you help with another one?

11. cgreenwade2000

YEs. Post a new question

12. Rosy95

Simplify|dw:1358281039137:dw|

13. cgreenwade2000

Tan^2theta + 1 = sec^2theta This is very useful to remember.

14. Rosy95

And can you check a question? The question is Which expression is equivalent to cos(pi-theta)? I got -cos theta. Is that right?

15. cgreenwade2000

I'll answer that one quickly before I finish your first problem.

16. cgreenwade2000

|dw:1358281166638:dw|

17. cgreenwade2000

Another good rule to remember. So, yes your answer is correct.

18. Rosy95

Thanks and for my second question, I am still confused. Can you explain more? It was the simplify one

19. cgreenwade2000

|dw:1358281344118:dw|

20. cgreenwade2000

|dw:1358281440642:dw|

21. Rosy95

Oh ok. So since cos^2 theta can be crossed out, you move the 1st numerator over the 2nd denominator. That makes more sense. Thanks!

22. cgreenwade2000

Well, it's not being crossed out. It's cos^2 theta divided by itself which is one. And then as fractions go, numerator times numerator and denominator times denominator.

23. Rosy95

Oh ok, Do you know how to do this one.... Solve $4\sin ^{2}x+4\sqrt{2}cosx-6=0$

24. cgreenwade2000

Post this one as a new question up top and close this question.

25. Rosy95

ok

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