Trigonometric Functions As Values of x

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See attachment.

25. sin(90° - theta)

26. [tex]sin^{2 } \alpha[/tex] + [tex]cos^{2 } \alpha[/tex] + [tex]tan^{2 } \alpha[/tex]

27. cos(90° - [tex]\beta[/tex]

28. tan(90° - phi)