Question

40 = 90^2/16 sinx cosx find x

Answer 1

Answer:

x = 4.545

Step-by-step explanation:

Given the expression

$40=\frac{90^2}{16} sinxcosx\\\\Cross\ multiplying;\\\\16*40 = 90^2 sinxcosx\\\\640 = 90^2 sinxcosx\\\\\frac{640}{8100} = sinxcosx\\ from\ trig\ identity, sin2x = 2sinxcosx\\sinxcosx = sin2x/2$

$Hence, \ \frac{640}{8100} = \frac{sin2x}{2} \\\\\frac{2*640}{8100} = sin2x\\ \\\frac{1280}{8100}=sin2x\\ \\0.158 = sin2x\\\\2x = sin^{-1} 0.158\\\\2x = 9.09\\x = 9.09/2\\x =4.545$