Find an equation of the tangent line to the curve
y=sin(9x)+cos(2x)

at the point (π/6,y(π/6))

If you differentiate the equation, you get dy/dx = 9cos(9x) - 2sin(2x)
after you have done this, you can put the x value into that to get the gradiant of the curve at the point given, which will be about -1.7
now that you know the gradient of that line, you can use the straight line formula to find out that line, which is (y-Yvalue) = gradient(x-Xvalue) which comes out as y- pi/6 = -1.7(x-pi/6), if you need to find this in the form y=mx+c you can just rearrange so that everything is on the right hand side, hope this helped

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!