A few days ago
Lee YW

if A is an acute angle,prove sin^2 A+cos^2 A=1.Then solve the equations sinx=y-1/5 & cosx= y+1/5?

for 0

Top 2 Answers
A few days ago

Favorite Answer

Draw a circle with radius 1. Then draw any line from the center to the perimeter (which is the radius) and make a perpendicular line to the x-axis from the point where the radius touches the perimeter. You will then get a right angled triangle inside a circle. Take the point where the radius touches the perimeter as (x,y). You will get cos A = x and sin A = y. Pythagoras theorem x2 + y2 =1 so cos2 A + sin2 A = 1.

To solve the equations just substitute cos x and sin x into the equation then expand them to get the y value.


A few days ago
Eagle Storm
like Albert said, but just to make sure that you get the point

x^2 + y^2 = r^2

_x^2_ + _ y^2_ = _r^2 _

r^2 r^2 r^2

cos^2 x + sin^2 x = 1