Write cosx - 3sinx in the form Rcos(x + a)
Rcos(x + a) = Rcosxcosa - Rsinxsina
By comparing cosx - 3sinx to the new expression, we can see that:
Rsina = 3 and Rcosa = 1
If we square both and add them, we can see R = √(12+(-3)2) [I would explain why to someone I'm tutoring]
Now that we know R, we can calculate a.
a = arcsin (3/10) [you may want to adjust the value]Then just write into the form...
OG
Related Maths A Level answers
All answers ▸y=20x-x^2-2x^3. Curve has a stationary point at the point M where x=-2. Find the x coordinate of the other stationary point of the curve and the value of the second derivative of both of these point, hence determining their nature.
Finding the tangent of an equation using implicit differentiation
How do I deal with parametric equations? x = 4 cos ( t + pi/6), y = 2 sin t, Show that x + y = 2sqrt(3) cos t.
Solve simultaneously: x + y + 3 = 0 and y = 2x^2 +3x - 1