7. f(x) =2tqx +cosx - sinx ;
f '(x) =(2tqx +cosx - sinx) ' = (2tqx)' +(cosx)' - (sinx)' =2/cos²x - sinx - cosx .
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8. f(x) =ctqx +x⁵ - sinx ;
f '(x) =(ctqx + x⁵ -√5) ' =(ctqx) ' +(x⁵)' - (√5) ' = -1/sin²x +5x⁴ -0.
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10. f(x) =x¹⁰(7x+15) ;
f'(x) =(x¹⁰(7x+15)) ' = (x¹⁰)'*(7x+15) + x¹⁰*(7x+15) ' =
10x⁹(7x+15) + 7x¹⁰.