Question 697013
(1)if sinA=7/25, cos=3/5 where A and B are acute, find without using tables:
I assume you mean cos(B) = 3/5
cos(A) = 24/25
sin(B) = 4/5
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a)the value of sin (A-B)
= sin(A)cos(B) - sin(B)cos(A)
= (7/25)*(3/5) - (4/5)*(24/25)
= -3/5
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b) the value of cos(A+B)
= coscos + sinsin
= (24/25)*(3/5) + (7/25)*(4/5)
= 4/5
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(2) Find the centre and radius of the circle 4X2+4y2-12x+5=0
Complete the squares
{{{4x^2 - 12x + 4y^2 = -5}}}
{{{x^2 - 3x + y^2 = -5/4}}}
{{{x^2 - 3x + 9/4 + y^2 = 1}}}
{{{(x - 3/2)^2 + y^2 = 1}}}
Center at (3/2,0)
radius = 1