3倍根号5sinx+3倍根号5cosx 化简
问题描述：
3倍根号5sinx+3倍根号5cosx 化简
答
x-y/7-x+y/10=1/2
即10x-10y-7x-7y=35
3x-17y=35 (1)
2(x-y)+5(x+y)=3
2x-2y+5x+5y=3
7x+3y=3 (2)
(2)*3-(1)*7
9y+119y=9-245
128y=-236
y=-59/32
x=（3-3y)/7=39/32
答
原式=3√10(√2/2*sinx+√2/2cosx)
=3√10(sinxcosπ/4+cosxsinπ/4)
=3√10sin(x+π/4)