Question

найдите значение выраженя если cosx=-0.7

Answer 1

7 *(1-cos^2x)+5cos^2x=7-7cos^2x+5cos^2x=7-2cos^2x=7-2*0,49=6,02

Answer 2

если cosx = -0.7

(cosx)^2 = (-0.7)^2 = 0.7*0.7 = 0.49

(sinx)^2 = 1 - (cosx)^2 = 1 - 0.49 = 0.51

7(sinx)^2 + 5(cosx)^2 = 7*0.51 + 5*0.49 = 3.57 + 2.45 = 6.02